Oh yeah! I have had problems with mouth sores since last June - continually. I went to the dentist in July thinking I had something stuck under my gum and was told I had a ulcer between my teeth. I told my rheumatologist and she said it could be a herpes virus causing the sores. As your immune system is pushed down by treatment, the normal herpes virus that many people have can become active in your mouth causing the sores. Ask for an oral rinse to help with them.

Yes I use the Listerine in the evening because I was getting sores

I had ulcerations: I changed my toothpaste to one of the Sensodynes that does not contain laurel sulfates, plus I added a daily Vitamin B12 to my regimen. Also I gargle with Listerine morning and night. No more ulcerations.

I have dry eyes & dry mouth which causes mouth ulcers occasionally.

I get them as well