Is nystatin and triamcinolone acetonide safe to use in my face for seb dermatitis? it's 1% strength.

No (very short!): The concentration of triamcinolone (tac) is too high. For the face, concentrations should be 0.025 or less of tac. Problems that occur if you use this high concentration is thinning of the skin and steroid acne. Usually no higher that 2.5% (hc)hydrocortisone (or equivalent) is recommended on the face. The otc hc cream is actually only 0.1%. You will need to see your doc for a prescription.