I get sores in my mouth. I gargle with a prescription mouthwash. I get the script from the dentist..

I only normally get ulcers in my mouth I first started the methotrexate and I got them right now because I'm in the middle of a flarer I gargle with salt water and I also found this orajel for toothache rinse that's awesome for ulcers also it is very soothing

I get them as well the best relief I have found is organic coconut oil you sort of glove it on it and it sucks the toxins out of it you can do this a few times A-day or more as it is completely natural but makes them go away much quicker than medicine! Hope this helps someone else!!

Triamcinolone paste

My dentist recommended a warm salt water rinse (teaspoon of salt in cup of water.) When I have sores I use it two to three times a day.

https://www.healthline.com/health/dental-and-or...

Definitely let your rheumatologist know though and see if they have any other recommendations. Prescription mouthwash greykat mentioned may be helpful for you if they are very painful. Mine are annoying, but not very painful. Hope you find relief soon.