Inflame edge of gum and tooth (4)
'tooth' is the definition.
(fang is a kind of tooth)
'inflame edge of gum and' is the wordplay.
I cannot really see how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
The remaining letters 'fag' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for fang that I've seen before include "Large canine tooth" , "Large pointed tooth" , "Animal's sharp tooth" , "possible poisoner" , "'Large, sharp tooth (4)'" .)
This clue is a quadruple definition!!
'inflame' is the first definition.
(thesaurus)
'edge' is the second definition.
(thesaurus)
'of' acts as a link.
'gum' is the third definition.
(thesaurus)
'and' acts as a link.
'tooth' is the fourth definition.
(thesaurus)
(Other definitions for bite that I've seen before include "Get teeth into" , "Light meal" , "Nip; nibble" , "Grip with teeth" , "Mouthful" .)