A supporter is upset about minor injury (8)
I believe the answer is:
abrasion
'minor injury' is the definition.
(type of injury)
'a supporter is upset' is the wordplay.
'supporter' becomes 'bra' (a bra gives support to breasts).
'is upset' becomes 'sion' (I can't explain this - if you can you should give a lot more credence to this answer).
'a'+'bra'+'sion'='ABRASION'
'about' is the link.
Can you help me to learn more?
(Other definitions for abrasion that I've seen before include "I ban oars over skin scrape" , "Grazing" , "A scrape or mark of rubbing" , "Scraped area on the skin" , "Scrape, scratch" .)