That’s what I’m leaning towards as well. The large spot on his lip looks like it’s raised up which would point more towards sore mouth but the others look more like staph. I would try treating for staph first. If they start to get really crusty then it’s probably sore mouth. There’s something a lot of people use that the name is not coming to mind, but I have successfully used tea colored iodine and wash the staph area, not really scrub vigorously but just kinda wash it (if that makes sense). If it turns crusty and is pointing to sore mouth there isn’t anything to cure it. It has to run its course but if he starts to go off feed, or you just want to do something for him, neosporn (spell check) to soften the scabs will sooth the pain.