Sunburn balm (4)
I believe the answer is:
aloe
'sunburn balm' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aloe that I've seen before include "Succulent plant (4) 5532" , "Bitter drug from a leaf juice" , ". . . . vera, soothing plant" , "Genus of bitter herbs" , "Plant source of purgative drug" .)