26 - male

Around 2 months ago a small lump appeared on my Chest just below my nipple. I thought it was an under the skin spot so I tried squeezing it, nothing, so used a knife to try and cut in to it and force the puss out. Nothing came out, not even blood. It scabbed over a little bit but stayed. 2 months later and it hasn't changed shape or size, it's just there. I assumed it was a keloid scar that had suddenly popped up as my mate has a few and it looked similar. 

It's a darker colour to the rest, Around the size of an ant. Approx 2mm diameter, I think I attached a photo to this message. I was going to make an appointment at the doctors tomorrow emergency but it's eating on my mind now, if anybody is online could say whether it sounds/looks like melanoma?