Hello! Can i get this skin only from the standard missions, without the "worlds pass"? I really want this skin because I have all the other skins (all chromas too). Now I have 180 tokens and i did, like, all the missions (except 1 or 2, i dunno). Hope you will help me thx y'all 
Don't know ;(... I think not but I might be wrong
You can get exactly 400 tokens from the free missions. Source: https://na.leagueoflegends.com/en/news/game-updates/special-event/learn-more-worlds-season-2018-event#faq But since you skipped 2 missions (you should have 200 tokens by now), you won't be able to get the maximum 400.
