I see what you mean. No change significant in size this whole time is of HUGE importance. Cancers usually grow in size, develop blood vessels to it, get very hard, and do not lose color when pressed on. So, it is very possible this is a little hemangioma, or venous lake-- these blanche when you press on them. That is a good sign, since melanomas don't lose color with pressure- and in the skin- melanoma is what is the most worrisome.
Your picking at it is probably causing scarring which is firm- so this could be a simple skin problem gone awry from scarring.
So again--- things that make us worry- - growth in size, darker in color that does not go away with anything, tiny blood vessels that are visible growing to it.
The picking could have made a dermatofibroma seem to grow from scarring, and change the dimpling. But, for me the reassuring parts are that the size is the same, it does blanche with pressure, and no pain etc.
If you keep picking something benign, it can turn into a cancer-
So stop picking at it, and have a doc see it. It is likely a benign skin structure, and does not need to be a fibroma- and the blanching part may simply mean it is a blood vessel structure, but instead of guessing and worrying, have someone look at it.
This kind of thing is easy to biopsy, and that could make 100% of your worry go away!
So stop worrying because of the dimpling you don't see. The things to worry about is if color turns black, size gets much bigger, the edges are jaggedy and the color is not uniform throughout.
I have a hunch all the changes are from picking at it, not because it is a tumor that is cancerous.
So, take a deep breath. Stop picking. And keep your appointment.
You will have a much clearer diagnosis then.
Hang in there, stop worrying so much.
There are many more benign things we see in the skin than there are cancers.