Hello and welcome. My name is ***** ***** I'm a biologist with a special interest in reptiles. I'm sorry to hear that Blaze is having some problems. These changes are reason to be concerned.
The first thing to do is check your temperatures. Under the basking light, it should be 105*F to 110*F. The cool side should be 80*F to 85*F. When temperatures are just a little bit too cool, it can be months before we see the effects on a dragon.
I'll give you a first aid measure that may help with the constipation. Get some prune baby food. Drop a small dollop right on the end of his snout. Most of the time, reflexes will cause them to lick it off. Wait about 45 minutes. Then prepare a shallow warm bath consisting of 1/2 warm water and 1/2 Pedialyte (yes the kind for human infants). Soak Blaze for about 20 to 30 minutes. After the first 10 minutes, with him still in the water, gently massage his underside from front to vent (where droppings pass out)for an additional 10 minutes. That may be enough to help him pass some feces. Be sure to supervise closely.
I would discontinue the mealworms. They are not a good food because they contain too much chitin and can't be digested properly. They may be the cause of the constipation. Over time, the chitin accumulates in the intestines. They're OK for some other lizards, but not for beardies. . Crickets that are no bigger than the space between your beardie’s eyes area better choice. Silk worms are another excellent food. I'm going to give you a link to a reputable and easy to understand site for information on feeding because there is too much for me to explain here:
Please check your temperatures and adjust them if necessary. Try the prunes and the soak with massage. After you do that, let me know how Blaze is doing, and we'll proceed from there.