Relieved the head cold had come to an end (6)

I believe the answer is:
ceased
'relieved the head cold' is the definition.
Although both the answer and definition are past participle verbs, I don't understand how one could define the other.
'come to an end' is the wordplay.
'come' becomes 'd' (I can't justify this - if you can you should give a lot more credence to this answer).
'to' says to put letters next to each other (I've seen this in other clues).
'an end' becomes 'cease' (to cease is to come to an end).
'd' after 'cease' is 'CEASED'.
'had' acts as a link.
Can you help me to learn more?
(Other definitions for ceased that I've seen before include "Stopped, quitted" , "Concluded" , "Stopped, ended" , "Stopped, desisted" , "Finished" .)
