Hi Ellie, I once nicked myself shaving when I was 19 and it turned into a spot on an area close to that area about 6mm and it popped. It was sore but went away but I had it checked to make sure it wasn't an infection or anything.

You really have two options, the first is tell you mum and go and get seen, trust me she'd want to know if you were scared you had cancer. Or find another gp close by.

 
Normally there are also sexual health clinics which have gyno nurses and doctors that can examine you. In Glasgow there's the Sandyford. They're not just for std testing they also do smear tests and examinations etc.

Im not saying I think it's anything to be concerned about, especially at your age, but I would always say get it checked. Never leave anything you're genuinely worry about. 
Trust me when I say a bit of embarrassment for a 20 minute check up is majorly less hassle and embarrassing  than weeks / months of anxiety or having something relatively mild turn into something serious because of embarrassment. There's nothing you can show your nurse or gp that they haven't seen a million times over.

nic x