It's not that uncommon for a collection of blood to appear under the skin flap behind the ear. I have found them avoidable through the use of fibrin glue over the last fifteen years but they can rarely occur. These jelly like clots absorb fluid and liquify and sometimes require repeated needle aspiration or drainage. Delaying may have negative effects on skin circulation if aspiration or drainage is necessary but is avoided so make sure that your doctor has seen you before problems can develop. Regards, Jon A. Perlman, M.D. FACS Certified, American Board of Plastic Surgery Member, American Society for Aesthetic Plastic Surgery (ASAPS) Beverly Hills, Ca.