My baby is 8 months (on Sunday). He’s been drinking Similac No Spit Up since he was 3 months old and…

My baby is 8 months (on Sunday). He’s been drinking Similac No Spit Up since he was 3 months old and has done amazing on it . Now for the past 3 days he is breaking out on his face arms and legs in little bumps (I was thinking maybe from the pollen) and is also very gassy (burping ALOT). Has any had this issue with your older babies ? With some research I’ve found his symptoms to be bc of a milk intolerance. If this has happened with yours, what did you change the milk to?