You want a skill reset?

I'm sure it would expire when you tried to use it, as the Resistance boxes did. That remains to be seen, though.

Unless someone was able to successfully pull that off with Big Bang.

I had resistance boxes on an old mech I left when I quit for about 6 months and when I came back and tried to open them (they weren't pulled from my inv) it said they had passed their expiration date and would be removed, and were removed. Same with the exp caps on my main.