It will take anything up to 6 weeks for your milk to be free of dairy. Many babies (including mine) who are cmpa also react to beef and soya. We were told by paeds to cut all of these out at once to get my bm clear of them all. Then test 1 at a time to see how baby reacted.
Looking back we had symptoms from day 1 but because they were not gut reactions they were missed. Our symptoms were breathing/coughing problems, excema, failure to thrive (but no vomiting, refusing feeds or anything like that) in first 6 months. Not picked up until we started weaning and she reacted with hives, running eyes/nose, swelling face etc on direct ingestion.
She was c8 months when diagnosed. I followed dairy, beef and soy free diet for 3 months. Allergy Specialist paed then put her on piritin and recommend I resume normal diet. She said kids who are bf by mum with normal diet with antihistamine are more likely to grow out of allergies quickly. Although by this stage she was 11 months so not feeding as much.
She's now 16 months, still feeds 3/4 times a day. I have normal diet and she's off all meds. She has failed all reintroduction ladders for direct ingestion, so still can't have dairy, beef or soya. She also reacts to strawberry, raspberry, pineapple and rye.
The cmpa Facebook pages are brilliant.
Good luck