I understand your concern, but you are worrying far more than you need to.
Melanoma-in-situ is almost a melanoma, but not quite. Pathologists often have trouble telling whether a small lesion like yours is that or a mole that's not quite even a melanoma-in-situ. Either way, the thing has to come off, as yours did. Your GP is not correct that the negative second biopsy tells you it wasn't melanoma, because the second biopsy shows only what was left after the biopsy, and all they found was scar tissue, which just means that the biopsy got it all. This is a good thing.
Having one melanoma does not mean that all your other moles are melanomas or almost melanomas. It is normal to get new moles till you're 40 or 50.
All you need to do is have your moles checked head-to-toe every 6 months. You have already done this. You do not need to have all your moles removed. You may not need to have any removed, ever.
Now you need to deal with your anxiety. Counseling and perhaps medication seem to me to be a good idea. Once you get past this, you can get on with your life. You're actually quite lucky that the doctor took off what you had at such an early stage.
Take care.
Dr. Rockoff
you ll continue to get new moles until the age of 40 or so, not all moles are bad,and depending on where the mole is located, it can have varying degrees of atypia. There is a lot of research on this at www.pubmed.com moles on acral parts of the body have been known to have more atypia, probably because of consistant trauma, and inflammation.
So NO not all moles are bad. but always keep an eye out, a pass through scan of ur body, 1 time a month is enough, i think.