Re: Mole that grows back - Partial after removed?
Normally, it can be unusual for a mole to grow back once it's been removed. This is especially true if the mole was removed and biopsied. What happened 3 years ago? Just a simple biopsy? Did you have a wide excision?
I would imagine you doctor now will want to biopsy this new growth to see what might be going on. Do you have any idea how long this new growth has been there? Since you have yearly checks, I'm presuming it's been within a year. That's a good sign.
For your question as to how fast skin cancer grows, it depends on the skin cancer. Basal and Squamous Cell cancers are rather slow growing - but should be taken seriously. Melanoma is aggressive and grows quickly. I suppose I could use myself as an example. I first noticed a faint freckle on my knee around the end of October/beginning of November 2006. By mid-December it had developed into what I thought was a mole, about 1/8" in diameter, and slightly raised. I had it biopsied in February 2007, and it was diagnosed as melanoma, with a Breslow depth of .7 mm. That's still thin, but I had nodular melanoma, which means it grows down instead of spreading outward. At 1 mm, the doctor does lymph node biopsy. I think my melanoma was growing at more than .10 mm a month, give or take. That may or may not be true for everyone, and it can be very different between nodular and superficial spreading melanoma.
My suggestion would be to follow your doctor's advice. I imagine you will be going through another biopsy. See what that says, and go from there. Be sure you get in for a biopsy as soon as you can. You are probably early enough the doc can remove all of this in a biopsy. Just take this one step at a time, and you will be fine!