Welcome to HW!
Wow, MS and now this. Sounds like an awful combination. Have you been diagnosed with epilepsy or are the seizures a complication from the MS?
My mom (has epilepsy) has been through that every time they change her meds—her seizures increase and she almost always has grand mals. She hasn't bitten her tongue in quite some time, not sure why though, because she gets pretty banged up every where else. Sometimes meds don't control the seizures 100%, so you just have to keep trying until you find the right one for you.
Hang in there. I hope better days will come soon.