My left arm went numb, then seized back on itself--hospital thinks it's migraine triggered seizure. Is there medication for this?

There's more going . on than you're describing and needs to be worked up by your PCP and a neurology referral. This can't be done by yourself. Difficult to answer without knowing the clinical details. Seizures have to be taken seriously. Good luck and best regards on working with the medical care team you'll have supporting you. This will lighten your load. :D .