Is this melanoma? Starting to ulcer?

I've had this mole since March 2017, when I first noticed it it was painful like a pimple but the pain subsided a few days later. I accidently scratched it off about 2 months ago while scratching my back. It bled scabbed and healed... Today I took a picture and noticed it looks to have a spot in it. I can't really see it since it's located on my back. Does this look like it's starting to ulcer? It does not appear to me to have changed shape at all since I first noticed it, it doesn't hurt itch or bleed other than the time I knicked it with my nail. I constantly rub at it to see if it causes pain and it doesn't. I have an appointment with a dermatologist at the end of the month I just want to know your opinion. Thank you for your time. Pictures #1 was taken April 2017 Picture #2 was taken today 8/9/2019