Mamas who breastfeed with baby with an allergy..

How should I see if he outgrew his dairy allergy? Haven’t had dairy in months. I look at anything and everything that may have dairy in it. Which is like everything I used to eat before so I completely switched my diet around. When would it be ok to try it again to see if it still bugs him? I know they say they usually outgrow it and my son is 6 months old tomorrow.

He had tiny bits of blood in his poop when he was 2 months old so they assumed it was dairy allergy