Are you routinely exposed to formaldehyde at work? You should talk to your doctor about that and how you can avoid it.   If you are not frequently exposed at work, then the easiest thing to do is simply avoid formaldehyde and products that contain it.   Read labels carefully or seek hypoallergenic products that typically do not have powerful chemicals in them. The problem seems to happen primarily on your face -- are you sure it's formaldehyde you've come in contact with? You should talk to your doctor or get a referral to an allergist to make sure there isn't some other subtance that may be causing the reaction.