Your clan can still consider you a child, and your Keeper sees this mission as a way to show you how the world is so you can appreciate how the Dalish are or something. It just made roleplaying anything other than a Pro-Dalish Dalish ridiculous, and that shouldn't happen for a character-driven RPG.
I didn't find it ridiculous at all, actually. My elf was just a standard elf until he went to the conclave and seeing the world made him question his dalish beliefs. He considers his vallaslin a silly mistake of adolescence.
My other Dalish elf was very Dalish, and did consider her vallaslin a point of pride, but I could have played her differently to just ignore them as a cultural ritual that she went through that had no major significance to her, just something that everyone did.
I'd rather my Dalish ignore their Vallaslin than ever be considered a child, but that's my personal belief because I like the tattoos.