Adult Female 130 Pounds 40 Yr Old. Prescribed Silvadene Cream

Adult female 130 pounds 40 yr old. prescribed Silvadene cream 1% for topical treatment of a grease burn (approx 1inch wide 3 inch long). 6 days past the burn, regular antibiotic ointment did not seem to be doing enough. Silvadene recommended. It seems to be working right away. 6yr old son had anaphalactic and almost fatal reaction from one dose of Sulfa antibiotic for a sinus infection. We now keep an Epi-pen for him. Should I be concerned if he should accidentally touch this ointment as it is in an exposed upper chest area right below my collar bone (where a necklace would hang). I am concerned a random hug or touch will cause more harm to him, than help to me. Thanks!