Is this a cold sore? one area of my lip started to tinging last night then when i got home its forming into a bump. the weather has been cold and hot

Oral herpes: The longer description is not typical of oral herpes (cold sores), but the briefer description could be. If the bump becomes blister-like nad/or in a couple of days an open sore that later scabs over, this would be typical for oral herpes. See a doctor if any doubt at all: prompt treatment with valacyclovir (Valtrex) or acyclovir can speed healing. OTC treatments do not help at all.