Possible CMPA???

My little one is 12 weeks old today. She has been ebf since birth, approx 2 weeks ago I introduced the odd bottle of kendamil formula because we had a family issue which needed me to be in the hospital for longer periods. Since then this rash on her face has become awful, she rubs it a lot 😢 I have stopped the formula? If it was the formula will this kick start an allergy that could carry on when I am ebf and consuming dairy products? How long until that formula is out of her system and this clears up? I am not certain it’s cmpa as she typically doesn’t have the other symptoms but it seems to convenient with it happening when I started the bottles. Just wish I could take it from her