A big welcome to Cancer Chat. If you noticed a mark which has got bigger on your arm, it would be worth just for peace of mind to book an appointment to see your GP if you haven't done so already. Your doctor will have the expertise to tell you what this mark might be so don't hesitate to ring your surgery to book an appointment to get this looked at especially as it has got bigger so it's a good idea to have it checked.
I hope you manage to speak to a doctor soon about this and that it all turns out to be nothing of concern.
