Did your phlegm taste sweet like e-juice, or did it taste like blood? I'd imagine it was blood. My doctors have told me brown means old dried blood, and pink is usually fresh blood. And before that sets off and red flags in your head.. if you're in the northern hemisphere, it's winter.. the air is just starting to dry out in my area when we're used to 80% humidity. It's also a season of post nasal drip, and other illnesses like strep, bronchitis, and sinus infections. I had something similar happen to me last year when I had decided it was time to take up vaping again, and sub-ohm vaping was the new rave. My juice tasted so yummy, I just kept puffing and puffing and puffing and puffing.
The next morning I coughed up bloody mucus.. now I anticipated some brown mucus as what usually happens when I switch from a streak of smoking cigarettes to vaping. But it was red and pink. It freaked me out.. but the reality of it is that I likely dried my sinuses out and I definitely suffer from a post-nasal drip. I don't remember exactly but I may have had a sore throat as well. You bleed sometimes when those things happen, and I'm sure a massive vape session could irritate that. I've not found a juice that will stain a paper towel when I exhale through it. I mean.. my mustasche is getting longer lately and it ends up soaked in vapor condensation especially with this cool air around us..so I wonder what's going on in our lungs from time to time.. but not enough to concern me. My experience has been that vaping has allowed the health issues that smoking caused a chance to clear up and heal, at least somewhat. And the rare times that I do get sick these days, which occurs way less way less frequently than it did while smoking, I don't feel as miserable as I would've on the cigarettes.
You say your throat's sore? I'd imagine there's some post nasal drip. You also don't mention what nicotine strength you juice is but you do mention you went straight to a sub tank.
Me personally, I started vaping on a 510 atomizer with 24mg strength like 80%/20% 70/30 50/50 juices.. If I tried to do that on a low resistance or sub-ohm build that would choke me out faster than a professional mma fighter.
I use 3mg 100% VG juice. 6mg is too harsh for me on a sub ohm build. Sometimes I'll mix a 3mg and a 6mg bottle of the same flavor for around 4.5mg... and being someone who could smoke 2 packs a day after 20 years of smoking, that can give me a nicotine rush like 24mg would before anyone knew what a rebuildable atomizer was.
Now - I'm not saying any one of these things is what caused this to happen to you. But, it's some food for thought. I'd suggest trying not to get carried away on the vaping for a day or two to give whatever's irritated a chance to heal. If it never happens again I'd say you have nothing to worry about. But I'm not a doctor, and even if any doctors do respond to you in this thread, they won't be able to diagnose you over the internet.. I'm sure it'd be difficult even in a skype situation. If you're concerned I'd schedule an appointment for as soon as I could afford to.
