Respite during cellulite reversal (4)
I believe the answer is:
lull
'respite' is the definition.
(lull is a kind of respite)
'during cellulite reversal' is the wordplay.
'during' indicates the answer is hidden within the clue.
'reversal' shows that the letters should be reversed in order.
'llul' is hidden within 'cellulite'.
'llul' back-to-front is 'LULL'.
(Other definitions for lull that I've seen before include "Period of inactivity" , "Short spell of calm" , "Subside" , "A calm period as in a storm" , "Short period of calm" .)