Thank you for your query on Healthcare Magic.
Infants in the early months have a slight erythematous rash
which usually decreases without any application.
Some times atopic rash which is known as eczema
will start with rash on cheeks.
Don't change the formula without a doctor advise and unless it is consistently proved to be the cause for the rash.
Don't apply any baby acid products as you mentioned without a prescription as these may cause contact dermatitis
due to irritation by the ingredients.
Physical examination by your Pediatrician
is necessary to diagnose the skin condition.
Hope I have answered your query.