Recently, I've noticed a mole on my arm has started going scabby, and it's turning black. It's hurt when I touch it, it sends like what i can describe as a shooting pain down my arm and it aches when I'm not touching it, I noticed it on Sunday as the scab started bleeding it wasnt as black then, but since then, it's grown a tiny bit and turned really black. 

I'm going to try ring the doctors about it but it's hopeless trying to get an appointment these days. Does it sound like I've reason to worry and ring just don't want to be wasting there time