Hello, so I'm wondering if someone has anyone insight on this or what I should do.

I'm 27 and have a 2mm (in surface area), flat mole on my abdomen (it's almost like a circular freckle, I've never really paid much attention to it). It was a medium-dark brown colour like a few small ones I have on my arm. A week ago however, I noticed that the area now has a scab and the mole cannot be seen. The area isn't raised but I've noticed a lighter patch around the scab. It hasn't been bleeding/weeping and it doesn't hurt or itch. 

I went to my doctors and they barely looked at it (no scope to get a closer look etc), and just said I have probably caught it without knowing (although it was completely flat so not sure how that would've happened?). They then said to just watch to see if it gets bigger over 3 weeks and if it does to call back and they'll refer me.

I don't feel as though they were very thorough, I was in and out in a few minutes, but I'm worried about it and scared to call back in case I'm wasting their time over something so tiny. But then I'm worried that it's cancerous and leaving it 3 weeks won't be safe.