My baby scratched me very hard down the side of my face. what do i do to ensure healing and prevent scarring? can i use bactroban (mupirocin) ointment i have?

Simple treatment: If there is no evidence of infection then plain vaseline on the site to keep it moist will give you the best chance at healing with minimal scarring for most superficial injuries. Topical antibiotic ointments usually don't do much for you unless the wound was dirty (baby fingers can be dirty sometimes). If you are concerned then please see your doctor.