Cows milk protein allergy

Has anyone’s baby had this & grown out of it? So he was diagnosed somewhat early on around 6-8 weeks & I had to stop breastfeeding & trial formulas before we found one that worked. He’s 9 months now & they said to start introducing “baked milk” first then maybe cheese then yogurt to see how he does. Has anyone had to do this & their baby not been fine? If so what symptoms did they have? I’m so scared to start trying stuff but know we have to... I did give him a few bites of banana bread the other two days & to me he’s seemEd a little more fussy, but I don’t want to assume the worst bc it could be related to anything ya know? Just hoping someone can relate...