Acid

Hi everyone, I've been following this forum for some time now and today I finally registered. It's my first post here so please be gentle :) I think nobody debated this, so here it goes! I always were curious with the fact of aliens having acid instead of blood. And I was even more intrigued with this when I saw the trailer and saw that one of the guys seemed to have acid or something similar on his face. Like it was already debated here...probably this guy got infected on that scene. After that his body starts to have some changes, he starts mutating into something else. Can one of this changes be acid instead of blood on himself or in the alien that will birth after he has sex with one of the crew members (Shaw)? It's probably just one of my crazy thoughts but I would like to know what you guys think about this.