Joining a little bit late but wanted to add a few things, hope this is informative for people.
When you quit smoking, your body starts expelling the chemicals. It is very common to have an increase in mucus production. Tobacco smoke will dry out your lungs - much like smoker's cough. Once you can clear out all that mucus (remember, it's your body trying to get the nasty stuff out of you), you will feel better.
PG/VG are very drying to some people, they can be hydrating to others. There can also be allergic reactions to either of them. You need to be careful and pay attention to your body. If you feel thirsty, you need to drink. If your mouth is dry, drink!!
There can be a long adjustment period to vaping, particularly if you have not ever truly quit smoking. The first few weeks are horrible - you are coughing up stuff, you will be short of breath, might feel like your chest is full of stuff, sore throat, loss of voice, etc. Sometimes you have to get worse to get better!
The biggest "side effect" I have had from vaping, which may be unreleated but there's no way to tell - is extensive sinus dryness. I have always had sinus issues (prone to sinusitis, pharyngitis, laryngitis, etc.,), even when smoking, but vaping now has them completely dried out - and it was like that before it became winter and the house got all dry. Georgia has humidity up to 90% on most days from June - September... and I still felt extremely dried out. The only thing that has been able to help me is using a NetiPot. I've noticed quite a bit of improvement over a short time - it also took care of my nagging soreness in my throat.
I know my body is healing... it just takes a long time. I have lost my voice from vaping, mainly because I wasn't drinking enough water.
I do not use any particular blend of pg/vg. I have tried all of them and not noticed a differerence. It might be the one area of my life where I don't have any physical complications, LOL!