Dermatolog said my mole was normal(a year ago)but it has shrunk in size a bit.no other signs of melanoma.should i be worried?is this normal?cancerous?

Don't worry see Doc: While a lot of moles can be non cancerous. It would be a good idea to follow up with dermatologist to get a biopsy of the mole especially if there has been any change in size, color, border, sensation, texture. Worry does not help you at all.

Regular observation: Make sure your dermatologist is looking at it about every year. Moles or lesions can change. Hope this helps.