School head yet to deal with inflammation (4)
I believe the answer is:
stye
'inflammation' is the definition.
(I've seen this before)
'school head yet to deal with' is the wordplay.
'head' indicates taking the first letters.
'to deal with' is an anagram indicator (deal with can mean to organise or sort out).
The initial letter of 'school' is 's'.
'yet' with letters rearranged gives 'tye'.
's'+'tye'='STYE'
(Other definitions for stye that I've seen before include "Eyelid problem" , "Eye problem" , "irritation to the viewer" , "Eyelid sore" , "Ocular inflammation" .)