How could i go about making a cure for dermatographism?

Won't happen: If anyone offers you a "cure", put your hand over your wallet. Antihistamines can be worse than the dermatographism itself. Omalizumab can control urticaria but won't cure this. Here's the truth -- most infections, surgical diseases, chemo-sensitive cancers, and a few counselling / situational problems can be "cured". Everything else in medicine is about managing stuff. Best wishes.