There was a very small bit of blood, like a little less than a drop, so I doubt I hit a vein. When I ran trest back in december/january, I hit veins quite a few times and never had the coughing. That's why I'm thinking its the dien.
Sweating is normal, nothing extra.
I've been thinking about doing knee wraps, but normally I can go heavy without my knee complaining too much. I think its because I've been avoiding real squats for a while and just doing leg presses in the machine. I'll give it a couple more weeks and see how things turn out.