Yes, large abrasions can take a long time to heal, and they heal from the margins inward. Unless your doctor told you otherwise, I wouldn't bother with the aquaphor; it is intended more for "minor post-operative wounds or defects," not large wounds. The silver sulfadiazine cream is bacteriocidal and will help prevent infection while the wound is open.
In the hospital where I worked, Mepilex had largely replaced Tegaderm as the preferred dressing for abrasions and open wounds, at least at the time I retired three years ago.