Hi Barb,
I've had allergic reactions albeit they were quite mild. Mainly slight skin rashes but nothing major. My vapes are all 80:20 PG/VG mixes, running off my Ego-T (although I've recently switched away from using tanks - don't like em). If you think you are allergic to PG, then try a higher concentration of VG, something like 60 PG, 40 VG and see how that goes for you. If you still see the symptoms, then you gotta try cutting down on the vaping, or go back to analogues for a week and see if the rashes subside. That's the only way to tell what's going on because there are so many factors at play here. Process of elimination is what you need to do right now.
VG is vegetable glycerin which you can get at your local supermarket while PG you can get at the chemist. But like Christopher said, most eliquid vendors will stock VG as well and you might as well order a bottle of it on your next juice purchase.
100% VG, I've never tried, but I've heard that it can really gunk up tank systems, so the best way is to get a cheap atty like the 510 and direct drip into it but it's quite troublesome and after a while of doing this, it's likely you're gonna miss your tank
Mech