milk alternatives "Ripple pea milk"

My son turned 1 on the 10th of Feb. We were slowly transitioning him to milk he is still breastfed and has dairy based formula as a supplement. We first notice a rash on his chin and chest after starting dairy about a little more than a week ago I figured it was from teething/drooling so I just made sure to keep him dry with a bib. Yesterday I gave him about 12oz total of milk by night he was covered in a rash but no breathing difficulties. Dr told me to hold off on milk and suggested soy, I'm not a fan of soy and last thing I want is another reaction. Have any of you moms or dads tried ripple brand pea milk. I'm just curious how your toddlers reacted.