Thank you for getting back to me. the bump you have described could be one of several different types, but it seems most likely that it is an abscess. Live crickets should never be left in the cage with a lizard. They bite the lizard while it's asleep or resting, and the result is a nasty infection. I suspect this may be what happened to your gecko. I know you would like a home remedy, and I would like to give you one, but this is one of those cases where a vet is called for. This link will take you to a directory of reptile vets:Link
I would get rid of the calcium sand. While it doesn't cause abscesses, it can aggravate any infection. Despite the fact that it is highly recommended by pet stores, more often than not, it leads to impaction. It is not really digestible. If you want to use sand, play sand is much better. A solid substrate, such as reptile carpet or ceramic tile, is best of all.
The temperatures in your enclosure are a bit too cool. You want a minimum of 82*F. The temperature gradient in the tank should be 82*F to 88*F day and night. An unhealthy gecko is better off with warmer temperatures.
I’m also sending along a care sheet, courtesy of Joan, another of our experts. You can use it as a checklist to make sure all the conditions are right. If you have more questions, just let me know by clicking on REPLY. I hope your gecko will reach a full recovery.
Leopard Gecko Care Sheet
The Leopard Gecko is originally from Pakistan, India, and a few other countries in Asia. They actually live on hard rocky outcrops and they are nocturnal (active at night). They prefer temperatures between 82 and 88 degrees all day and night. They grow to between 8 to 11 inches. Leopard Geckos are available in a wide range of colors and patterns which are the result of selective captive breeding. These include albino, ghost, striped, jungle, Leucistic and high yellow. These colors have been made possible through selective captive breeding. Leopard Geckos make wonderful pets for almost any age person. Leopard Geckos also make good long term pets. They can live over twenty years. Never grab by tail it will break off.
Leopard Gecko Housing: A male Leopard Gecko should never be housed in the same cage as another male leopard gecko because they will fight and possibly kill one another. A male can be housed with several females without any problems. I do not advise housing leopard geckos in the same cage with any other reptiles. A single Leopard Gecko can be kept in a ten gallon tank. For a male and a few females a twenty gallon tank or larger should be used. The cage should have a screen lid on top of it to prevent any escapes. Leopard geckos need places to hide and sleep during the day so you must provide a couple of hiding spots. They need a warm hiding spot and a cold humid hiding spot. Just put one hide box on the side with the heat light and put the humid hide box on the side that does not have the heat light. I actually prefer an under the tank heater for heat source rather than a light since the geckos are Nocturnal. For the humid hide box, Paper Towels work well and easily replaced inside a hide box. You can make your own humid hide box from a small plastic shoe box or from a margarine conatiner. Cut a hole in one end of the container and place moist paper towel inside it. The humid box should be cleaned out every week and re moistened. A humid hide box is needed so that the gecko can go in it when it needs to shed. The humidity helps the old skin come off.
Substrate: There is an abundance of products on the market that claim to be safe substrates. All Loose Substrates (Please note the link above) however are not safe to use. A substrate is what you put on the bottom of the cage for the lizard to walk around on. If a Leopard Gecko ingests any of the substrate accidentally, the substrate must pass through the digestive system. Trust me they will ingest substrate, sometimes on purpose. If it does not easily pass through the digestive system compaction will occur. Compaction is an extreme blockage of the digestive tract and is often fatal. Some substrates that I consider unsafe because they can cause compaction are: sand, bark, Calci sand, crushed walnut shells, lizard litter, gravel, aquarium gravel, and coconut fiber. The safest substrate is using paper towels or plain newspaper, non-stick shelf liner , cage carpet or ceramic tile. For any leopard geckos that are younger than six months I advise using paper towels or plain newspaper until they are at least six months old. Calcium sand is not fully digested no matter what it claims. The stuff just does not break down completely. . Leopard
Gecko Heating and Temperature: The cage should be between 82 to 88 degrees all day and night. There is two basic ways to heat the cage. One is to use a under tank heater like heat tape. The other is to use a black, or blue night incandescent heat light. I prefer to use a heat light. For a 10 gallon tank a 60 watt bulb should work depending on room temperature. Place the heat light on one end of the cage. By putting the heat light on one end of the cage it keeps that side warmest and allows the gecko to move to the warmer side with the light or to the colder side without the light as needed to regulate body temperature.
NEVER EVER USE A HOT ROCK, HEAT ROCK, OR ANY SIMILAR PRODUCT. Hot rocks heat unevenly and are notorious for causing terrible thermal burns. Do not buy a hot rock and if you know anyone who uses one, tell them to throw it away.
Leopard Gecko Feeding: Leopard Geckos will do very well on a diet of mealworms and crickets. I like to provide some variety in feeder insects to create a more balanced diet. Feeder insects I use are silkworms, mealworms, roaches and crickets with the legs on one side of the body pulled off. Crickets will bite your geckos while they sleep, these bites are prone to infection, so if you pull off one side of their legs then they cannot move around the cage and get to the gecko and also this prevents the crickets from climbing out of the cage. Gut load feeder insects for at least a day before putting them in with the gecko. Feed geckos insects that are not larger than the width of the head of the gecko.
Adults can be fed superworms, though I advise only feeding a couple superworms at a time. Leopard Gecko Vitamin/Mineral Supplement: For young geckos dust the feeder insects every other feeding or place a small feeder dish with supplement in it and some mealworms in the cage. For adults and babies place a shallow dish or a plastic lid in the cage with a teaspoon of calcium powder on it. The gecko will lick the calcium powder as needed. You still need to dust feeder insects every other feeding though with a vitamin supplement for young geckos. Adults use vitamin supplement once a week. Leopard Gecko Water: Use a shallow water bowl, fill with water as needed. Remove bowl from cage and clean out weekly.
Do Not Feed Pinkies