Hi. bmw I am glad you found your way here
It is possible to have infection and it travel and damage one or more branches of the trig nerve.
Have you seen a neuro. many times t.n. or even a compression will not show on mri.
By you applying heat to area you are warming the nerve and "calming" it down. some find heat helps others it is a cold compress.
I would strongly suggest you see a neurologist or pain specialist so they can diagnose you and help control your pain.
You are not alone. there are lots of understanding members here who "get it" because we all are dealing with the ugly pain monster.
see a neuro a.s.a.p. they are the best ones to know if it is t.n. and what meds you may need. and remember you have us here to help with questions and here for support.
Sending good energy and low pain to you.
PEACE
Tina ... usually it is BMW but that is a name one of the mods gave me a few years ago its short for Burntmarshmallow . but now we have a bmw so I am Tina


edit to say also read around this forum and the stickies up top have some very helpful links and tons of info.