Is this anything to worry about?

[BlackCatinaSantaHat]

I have a purple rash at the top of one of my legs (on the outside).
Am feeling tired but then I don't think I had enough sleep last night.
No other symptoms just lethargic.

I'd ring my gp personally asap, does the rash go if you put the side of a tumbler glass over it and press?

No but I'm feeling a bit less tired now. Do you think it is something to worry about if I feel o.k. otherwise?

I'd go anyway but then I have allergies that otc anti histamines dont touch.