Hang in there, I myself was allergic till about 3-5 and after much treatment 25 years ago! I outgrew my milk allergy

My LO reacted to normal formula as well and has been in the hydrolized formula since. He was tested for the milk allergy and it did not flare up. I think when we started introducing it manifested as excema. A dietitian we saw recommended starting dairy in this order:
Stage 1: mcvities or digestive biscuits, scones, plain cakes without icing, , cheese breadsticks, croissant, brioche, bread.
Stage 2:cooked in oven for at least 1/2 hour
Stage 3: homemade custard, cheese on toast, cheese crisps, rice pudding
Stage 4: uncooked cheese, yogurt, ice cream, butter
Stage 5: cow's milk not heated
HOPE THIS HELPS!