Ears do bleed a lot so don't worry that is common.
If you have any of the Kwik Stop or other powders used to stop a bleeding toe nail or if you have a styptic pencil for shaving cuts you can scrape off some of that and you can use either of those to stop the bleeding on the ear.
You can also see if holding an ice cube against the ear (in a plastic bag) above the cut by a little bit and over it will stop the bleeding by slowing blood flow.
You can also use some corn starch or flour in a pinch as a clotting agent to help stop the bleeding.
If your dog keeps starting the bleeding up again by shaking the head you can tape her two ears over the top of her head so they can't flap when she shakes them. Paper tape or vet wrap might be the best choice for that.
You can also use an old sock (depending on the dog's head size and the sock) and cut the toe out to slide the whole thing over her head like a snood to hold the ears against her neck to keep from reinjuring it. You can see a dog with a snood holding its ears down here for an example
Depending on how big the cut is you may want to consider seeing the vet about antiibiotics. If its just a little nick you may be able to treat your self by cleaning the area with betadine iodine solution and Neosporin or Triple Antibiotic ointment once you get the bleeding stopped.
If its a big slash then seeing a vet to see if it can be stitched might be a good choice.
This site may help you locate an emergency vet if you thing youneed one
Hope this helps you!
Any size cut can get infected of course its just usually easier to home treat smaller injuries.
If the ear is sliced through both sides for an inch or more you may want to see if a vet can repair it for you tonight. If you wait until morning the tissue might be too inflamed to repair.
If the ear is only cut along one side (ie isn't making a hole right through the ear) then you may be able to do home care.
But if you see any infection signs you may want to see your vet.
If the edges are close together they should heal up pretty well and if apart it would heal mor slowly. If there is tissue underneath it should heal. You'd want to use antibiotic ointment on the scab area to help it heal. Neosporin, triple antibiotic ointment etc.
You might have a scar on the ear but if there is enough hair it may cover it. It would be more obvious on a short haired breed.
If the ear is flopping, and its an upright ear normally, then you might want vet care if you need or want the ear to be standing when all is healed.
As long as the ear is not sliced all the way through it should heal back.
If it is sliced through so there is a gap from side to side of the ear then it may heal with a slit or notch in the ear.
A vet might be able to stitch or use surgical glue to put it back in place but you may have about a 6 hour time limit on doing that.
If you clean the area out well you might be able to get it to heal together using a butterfly type strip bandage to hold the edges together. If there is a lot of fur there it may need to be shaved before you clean the area and do the bandage.
You woud pull the two sides to eatch other from V to II and then put narrow strips of bandage across like stitching so it would look like this # XXXXX hold the edges together.
Do this on both sides (inside and outside) to hold the skin on each side together.
It can also be left to have a notch in it if that isn't a problem for you.
Its up to you, yes the ear will not look the same if you do nothing but the edges of the slice should heal over leaving a gap in the ear.
You can see a vet to try to get it put back together or you can try matching it up to heal together yourself.
I have seen dogs with notches in their ears from such injuries and it doesn't really bother them.
If it has stopped bleeding and you don't think you will start it again then yes you can use the neosporin now just coat it carefully and let it sit to soak in.
You can do that a couple times a day until its healed up.
Yes you can wait to apply ointment until the scab is well set on it.
I'd not leave her out in the rain beyond time to potty.