Is FDA-approved low level light therapy/LLLT a qualified medical expense?

I purchased an FDA-approved iRestore for a chronic, severe, medically-documented case of seborrheic dermatitis for $588.98, $639.35 in total (CA state tax ($35.04), CA county tax ($1.46), San Francisco County district tax SP ($8.03), and Orange Co local tax SL ($5.84)), to help reduce inflammation. Is this tax-deductible as a medical expense, and if so, does it require anything and would I hypothetically enter the pre-tax amount of $588.98 or $639.35, the full price/total after taxes?