Nervous crossing peak, in need of a pick-me-up (11)
I believe the answer is:
restorative
'pick-me-up' is the definition.
(I've seen this before)
'nervous crossing peak in need of a' is the wordplay.
'nervous' becomes 'restive' (synonyms).
'crossing' means one lot of letters goes inside another.
'peak' becomes 'tor' (I've seen this before).
'in need of' says to put letters next to each other.
'tor'+'a'='tora'
'restive' placed around 'tora' is 'RESTORATIVE'.
(Other definitions for restorative that I've seen before include "health-promoting medicine" , "Health-giving medicine" , "promoting recuperation" , "Pick-me-up" , "Tonic" .)