Anyone’s baby had this?

When my baby started solids at 6 months old he was totally fine with fruit and vegetable purees, but then when i gave him some baby puffs and baby biscuits at 8 months he started getting all red around his mouth and chin and sometimes white blisters/spots. I took him to see an allergy specialist who did a prink test for wheat and dairy and said he wasn’t allergic to them and that what he has could be an atopic dermatitis and to minimize food contact with his skin by using petroleum jelly on his face and neck when he eats. My son is now 9 months old and i have been using the petroleum jelly but he still gets the same reaction to some foods, i have not been able to pinpoint what exactly. Did anyone deal with this? Do you know what it could be? Do you think i should avoid any food that gives him a reaction?

I just need advice on wether to go see another doctor or to just avoid the foods that cause this or what to do. Thank you.

PS when i tried eggs he turned so red and his ears were so red and hot. Not the same reaction, just turned all red and hot. Is that an allergic reaction? Any idea?