Atypical nevus has repigmented in one month. Is this concerning?

I went to the derm for a one month follow up (to actinic keratosis on face) and asked her to look at a new 4mm mole on my back (wasnt there last yr). She did a shave biopsy as it met ABCDE criteria. Results were mildly atypical (both architectural and cytologic). This is my second mole with that result. Returned at one month post for yearly exam and P.A . says repigmented and needs excision (in 3 wk @ f/u for 2nd freezing of facial AK). How concerned should I be? What questions should I ask?