Yeah, an hour is a long time for an IM injection site to bleed...For future reference if it ever happens again, go out and buy a little box of corn starch and just keep it in your beardie first-aid kit for future use. I have a bearded dragon first-aid kit and a parrot first-aid kit, and with parrots they have blood feathers that if they break will cause them to actually bleed to death if you don't put styptic powder/liquid or cornstarch on it, so I keep both in both first-aid kits so I know exactly where it is in an emergency. Your beardie may be "a bleeder", just meaning his blood doesn't clot as quickly as most or is a bit thin, that's not unusual, or the vet who gave the injection may have hit a large arterial, not unusual.
If it ever happens again, go get the box of cornstarch and a wet papertowel or a wet q-Tip, then drip the wet q-Tip in the cornstarch or pour some of the cornstarch on the wet papertowel, a good heaping amount, and then put the q-Tip or the papertowel directly on the bleeding and apply very firm pressure for at least a minute without stopping. After a minute gently lift up the q-Tip or the papertowel and check to see if the bleeding has stopped. If not just repeat until it does stop.
You can use this for when your beardie cuts himself or has an accident, any time he's bleeding. The cornstarch is great to keep on hand at all times for pets (and yourself, lol) any time they're bleeding. It works just as well as styptic powder or "Qwik-Stop" liquid, but it doesn't burn like they do when used on skin. For bleeding toenails that you may have cut too short the styptic powder or Qwik-Stop liquid is actually better and doesn't burn as badly if on toenails instead of skin.