@princevince, no it's probably just from the change!! that's a super minor rash when we started solids my daughter got ones like that pretty often for the first few weeks until her skin got used to the change!! or maybe you fed him something slightly acidic! most baby foods themselves have absorbic acid or citric acid added to preserve them (I make my own due to this) if he was allergic it would probably be way worse!! my daughter went from no rash to big painful looking blisters in one poop!! and it made her face red and breakout!!!
my daughter didn't have problems until we started real food!!! she was allergic to grape juice and got blisters! it's heartbreaking I know but itl go away quick just make sure to change him if he's wet at all so it doesn't sting him at all!! @princevince