My face has developed a brown patchy mask like discolouration. Does anyone know what could be causing this? It seems to have appeared from nowhere and is really getting me down. It's the same as some women have when they are pregnant - I know I am definitely not pregnant. I am not on birth control either.
I do take carbimazole for thyroid problems - Grave's Disease - don't know if this has anything to do with it - but I have been taking them for 2 years and this has just started over the past month. I am 39 years old so don't think it is age related.
The patches started on my forehead and are travelling down past my eybrows and onto my cheek. It's as if they are joining together and growing in size.

I would be grateful for any advice.