I use petroleum jelly b/c of dry skin some reaction appeared small insect bite like bump on my left cheek what's the medical term?tia

Urticaria: It's a type of 'contact dermatitis'.

Hive/urticaria: It would be very unusual to form a contact allergy to petroleum jelly. There is likely another cause for your hive. If this persists, consider a virtual consult to discuss causes of chronic urticaria as there are many: http://www.aaaai.org/conditions-and-treatments/allergies/skin-allergy.aspx