Yellow tongue

Hi everyone,

I have rrms since 2010.

I have a yellow tongue, had it since november. It is not oral thrush.(mainly at the back of tongue) cant get rid of it.

Has anyone had this, i have been on Tecfidera for a couple of years.

Also have had h pylori and gastritis a few years ago. Which i took antibiotics for.

Wondering if this could been stomach problems, as i do get heartburn, or if it is to do with Tecfidera.

Thankyou for any replies.