In need of something on top for congestion etc? (4,4)
I believe the answer is:
head cold
'congestion etc?' is the definition.
(congestion is a symptom of a head cold)
I can't explain the remainder of the clue.
(Other definitions for head cold that I've seen before include "Ailment blocking the nasal passages" , "Common infection of the sinuses" , "What might block up nose and eyes" , "complaint" .)