Can a scar look better at two weeks post Mohs and then look worse a week later?

Following Mohs surgery and in fact after any surgical operation on the skin and underlying soft tissue there is a normal biological healing process which typically involves a time delay of 4 weeks before the wound is structurally intact, that is at minimal risk for opening up or "dehiscing" with stretch or pressure to the site and a full 3 months minimally before the resulting scar is stable.  During the first few weeks of wound healing it is not unusual for the scar to have a small degree of redness and if the borders of the closed wound were elevated from the outset it may take 2-3 months for this to flatten normally.  If there is increasing redness or increasing elevation of any recent surgical scar then this may represent an abnormal healing process referred to as hypertrophic scar or keloid formation and early intervention to help reverse this abnormal healing is recommended. 
There are methods to help control  the way a new surgical wound is healing and minimize  the final scar  appearance.   Mohs surgeons who are skilled in cosmetic surgery  can offer these additional steps  and  improve he final appearance of the scar  with special procedures  they are trained in.