Red lump diagnosis

[RabiedRooster]

Hi i have a DG which overnight has developed a red protrusion from the corner of its mouth. The tank has been going for 3 months now and everything has been fine. 40% Water changes every week. Not sure if he has just bumped himself and got wounded. It does stick out a bit which cannot be seen from the photos. Also he is acting as usual. No water params as im waiting on new test equipment. Any help will be appreciated.

 

[dkpate]

Do you think he might have gotten stuck somewhere? My DG's liked to squeeze themselves in the smallest spaces...
If it's not a giant lump, I would just keep the water clean for a few days, and keep an eye on the spot. If it gets bigger you might need to treat. It kind of just looks like a blood blister, like people get when pinched.