If my Fidough was damaged, and I evolve it to Dachsbun ex and use the "Time to Chow Down" Ability, does that Dachsbun ex also get healed of all damage?
Yes.
Source: Stellar Crown FAQ; TPCi Rules Team (2024-09-12)

Relevant cards

Note: All applicable cards may not be listed below.
SV7_67
SV7_67