As scary as that sounds, I still think it's early days and there is likely to be improvement - especially if there's some swelling/infection happening - that can disrupt nerve signals. I hope the Dr has some answers/reassurance for him.
Agree. Whilst everything is still tender and owie, it could be affecting how he is functioning at this point in time.

DH got over his infection fine, there has been no issues with how he feels during sex. The is the odd time that the testicle that got infected will ache, but nothing that affects his enjoyment.