My baby has a rash on his face. i think it might be eczema because his face is dry. can i put vaseline on his face?

Go to a doctor: Baby's skin is very delicate and it is not good to treat it with things that are fine for older children and adults. A facial rash may not be serious, but it may be part of an allergic reaction or something else requiring a prescription. Make an appointment or visit an urgent care clinic to avoid problems. Vaseline does not sound good, but ask a druggist for a baby product that won't hurt.