The rash really needs to be evaluated and monitored very closely being that you're on
lamotrigene as it can cause a deadly rash called Stevens Johnson Syndrome that can land you in the burn ward of your local trauma center.

I was prescribed Lamictal years ago when it first came on the market and my Pdoc told me to research it as has a black box warning from the FDA meaning it has some extremely serious side-effects that can kill you. My Pdoc suggested I research it which is why I know it can land you in the burn ward once the rash gets going.

Here's an article on it you should read.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905385/