Brown mole turned red, with white rim - when to see doctor?

[joh85]

A few months ago I discovered a new mole (at least I think it was new, or maybe it just became a bit more raised) on my forearm. The mole was light brown. This summer, however, the mole has turned pink. And now there is a white rim around it (the skin around it is not tan like the rest of my arm).
So this is a pink mole, 5mm in diameter, with a white rim that is 8mm in diameter.
What would you think this could be?
I am going to see a doctor, and I have an appointment at the beginning of September (regarding a different issue). That is a month from now. Will this be too long to wait, and should I try to get a doctor's appointment sooner?

[joh85]

Thanks
It turned out to be a halo nevi.

[Pum]

It could be a halo nevis in which case it probably will go away but it also could be something nastier and only a specialist can tell you. I think they can be hard to tell apart without the right equipment. I'd try and get it viewed before Sept just in case.

[joh85]

Ok, dermatologist appointment on wednesday. Still, nobody here who knows anything like this?