Thanks for your query.Based on the facts that you have posted it appears that you have developed bruising of your glans
after dry vigorous sex with your girl friend which later on scabbed and shade away.
Please take broad spectrum antibiotics along with anti inflammatory medication like Diclofenac
twice daily along with topical antibiotic
ointment like Neosporin
Get the prescription of medicines from your family Physician.
Ensure to clean your genitals with warm water twice daily.and use lubricant during sexual activities.