It may be nothing but hard to say without a clear picture. As you don't want to stress your snake by trying to hold its mouth open long enough to get a good picture, I suggest double checking your husbandry (temps, humidity etc.) and monitor the snake over the next week or two to see if there is any change in behavior, eating or discoloration in the snake's mouth.
If its a minor case of mouth rot, it could end up going away on its own. To best ensure your snake fights off the infection without medical help, he must be in a perfect setup, temperature and humidity wise with as little stress as possible.
After a couple weeks, check the mouth again, unless you see signs your snake isn't doing well before this. Signs like refusing to eat, drooling, listlessness etc. In which case, take him to a reptile vet.
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PHLdyPayne