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Normally there is temporary loss of hearing even in case of common cold
due to swelling of the tympanic membrane(ear drum) and infection of middle ear.Some times there can be pus coming from ear and in such cases there is a hole formed in the ear drum and can cause some loss of hearing which can be corrected after the surgical repair of the ear drum.Since you have complete loss in one ear and that is following chicken pox
then it can be possible if there is some damage to the auditory nerve
.Also you said that inspite of surgery you do not have hearing power then it is somthing related to the nerve.Please reconsult the operating surgeon for more detailed reasoning for your problem and the solution that can be done.