Came back holding the same deodorant that had caused the swelling (6)
I believe the answer is:
oedema
'the swelling' is the definition.
(oedema is a kind of swelling)
'came back holding the same deodorant that' is the wordplay.
'came back' is a reversal indicator.
'holding' says the answer is hidden in the clue.
'amedeo' is hidden in the letters of 'same deodorant that'.
'amedeo' back-to-front is 'OEDEMA'.
'had caused' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for oedema that I've seen before include "Excess of fluid in the tissue" , "Excess of fluid in tissues causing swelling" , "it gets bigger" , "Tissue swelling from bodily fluid" , "Excess of fluids in the tissues" .)