If I got the Rueful Axe as a reward for completing A Daedra's Best Friend, is there a way I can trade it in for the Masque?

I don't think so. Unless you're on pc.

Uhh oh. There must be away, this is what the wiki says "The Rueful Axe is not a Daedric Artifact. If you wish to obtain the http://uesp.net/wiki/Skyrim:Achievements you should return the axe for the Masque of Clavicus Vile."

Well, I couldn't say from personal experience.... but first, the wiki is produced by players, not the game company/devs - so there's a LOT of "not perfect" info in there.... and second, the only way I can imagine you could do that would be through the console on pc. Then again, I may not have all the relevant info since I don't ever do that quest (or any of the "get an artifact" quests) since I could care far MORE than less about things like achievements.

If the wiki doesn't tell you HOW to exchange it, I'm not sure where to direct you.

They probably mean reload to a previous save.

I would probably have to go and kick them in the balls. I did this quest long ago and I am now just reading about it, no way can I go back to a previous save.

Oh. You're probably right....

Well, I have confirmed it. If you choose the Rueful Axe and kill Barbas you will not be able to get the Masque. So to all of you console players like me, if you expect to get the Oblivion Walker achievement...do not keep the axe. I don't have a previous save I can return to so I am screwed.

Or they probably mean: return it before you kill Barbas because I think you have it in your possession for a while from retrieving it, right? Either way, I'm pretty sure that killing Barbas is the fait accompli.

Well before I knew about the Masque I did the evil thing that you would expect a Daedra would want you to do. How was I suppose to know that if I returned the Axe then I would get the Masque?

I got the Masque because I refused to kill the dog, but, yeah, I would assume the axe was the artifact.

you can get both hircine artifacts to make up for missing the mask

Have you confirmed this? This would be awesome for me.

confirmed. Theres a walkthrough on the uesp - here you go.

http://www.uesp.net/wiki/Skyrim:Ill_Met_By_Moonlight

also, ake sure you take the skull of corruption, dont destroy it.

Thank you very much, saved me from raging haha.

No problem. Also a good idea to do a quick uesp search on 'Oblivion Walker' if youre unsure about making a choice in daedric quests.