Sunburn salve (4)
I believe the answer is:
aloe
'sunburn salve' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aloe that I've seen before include "Bitter drug from a leaf juice" , ". . . . vera, soothing plant" , "Genus of bitter herbs" , "Succulent plant (may be bitter!)" , "Flower, maybe vera" .)