Mystery "Rash" for Years (Pic included)

[Ana_Miletic]

For a few years now, I've had this problem where my skin suddenly has a white bump (very small) appear with a red ring around it. It usually happens around the mouth area and happens randomly throughout the day. It goes away within an hour but I have no clue why it happens. It also commonly happens after I leave the shower. Is this something in regards to a temperature change? I just really want to know what this is because it gets rather embarrassing when I have a random red circle on my face :/

[maatson]

Change of temperature, leading to localized sweating, and release of histamine, formation of a little raised area, disappears soon.
Commoner in the generalized form, rare in localized areas as in your case.

[maatson]

Cholinergic dermographism, relating to change of temperature.
Interesting!