Doesn't appear to be mouth rot to me at all, at least not on the outside. It looks more like an injury, either from rubbing against something in the cage or wounds caused by crickets left in the dragon's cage.
The tail looks like it's going to fall off eventualy, from the left most indentation. This could be caused by crickets again, or unshed skin cutting circulation from the tail end. Could also be bite marks from cage mates, if your dragon isn't housed alone.
Mouth rot tends to be more inside the mouth, causing swelling, redness and often a cheezy like substance in the mouth. Drooling or having the mouth open unusually long (don't confuse with the regular mouth gaping dragons do while basking). If you don't see any cheezy stuff in the mouth, the redness etc may be from the outside injury. Though bleeding gums may indicate the presence of mouth rot anyway.
To treat mouthrot, which sometimes is a secondary or precursor symptom of Metalibotic bone disease (ie: MBD), you need to take your dragon to a reptile vet for treatments. These typically consist of antibiotic injections and/or drops you will have to administer to your dragon.
For the external injuries you can treat with any antibiotic cream/ointment (without any pain killers/relief included) such as polysporin. Just dab a bit on the mouth wound with a q-tip and on the injuries to the tail. Finally, make sure all uneaten crickets are removed from the cage before nightfall. It only takes a few starving crickets to cause injuries to your dragon while he sleeps.
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PHLdyPayne