Hi and welcome,
I would advice speaking with your neurologist but if you are not diagnosed with MS and taking any related MS drugs there's less chance of an adverse reaction you'd need to be aware of, MSers can also get herpies too just like anyone can, treatment shouldn't be a problem as far as i'm aware....
i found this answer for a similar question from a diagnosed MSer on medhelp back in 2010 when there use to be doctors answering neurology questions;
"There are antiviral drugs like acyclovir, valacyclovir and famciclovir which can shorten the episodes and decrease their severity. Acyclovir reduces the pain and number of lesions in the initial case of herpes and reduces recurrence. The ointment applied topically reduces pain, healing time and limits the spread. Though rare, herpes virus can cause inflammation of membranes and the cerebrospinal fluid surrounding your brain and spinal cord."
Hope this helps....JJ