What Causes The Outbreak Of Rashes While On Lamictal?

I believe I may be allergic to Lamotrigine. However, I had no problems with Lamictal. The rashes developed within 7 months of switchning from brand to generic. Allergy doctor is not interested in testing for drug allergy. Motrin gives me rashes but not as bad as these. I've had prednisone, and that cooled off the rashes for about 3 days each time. 2 drugs I'm trying for the 4th month with very little improvement: Hydroxyzine and Zyrtec. I had an additional drug but don't recall the name. I had to stop Lamictal because the insurance won't cover it. Even the generic + other drugs combined is too expensive.