Welcome to HCM
We understand your concerns
I went throug your description. I suggest you not to worry too much. What ever discoloration you mentioned, never corresponds to skin cancer
. This could just be a discoloration. Melanin deficiency
or concentration of melanin.
From the description you gave, I also have some doubt about your character. You are worried about your health too much. Small happenings in your body stress
you. Such condition is bad for now and dangerous if you continue to do so. Therefore no self diagnosis, no self medication
and of course no unnecessary thinking.
Hope this answers your query. Available for further clarification.