Hi
@drewskii and welcome to VU!
Yes, there have been instances of allergic reactions and sensitivity to PG, that is one of the main reasons Max and 100 VG juices were developed years ago. However, even though it's possible that you are having a reaction it seems odd that only recently after so many months of vaping a low PG juice you would just now be having a reaction. I would search the forums and google for "PG allergy" and try and find more info and discuss it with your doctor. In the meantime I would discontinue your use of your cheap juice and order some high quality VG juice like from Alien Visions E-juice. There are several other vendors that do all VG and organic VG, you can find them around the e-liquid section or search for them with Google...I pretty much have vaped the same brand of e-liquid when I buy premade stuff and I DIY a good chuck of my juice so sadly I am not the best person to recommend a bunch of places to shop, AVE just has one of my favorite juices so I recommended them because I can attest to their quality. I think Dr. Crimmy's has a max VG line and a lot of people seem to like their stuff as well. Ask you question over in the e-liquid section and I am sure you'll get a good shop list. And stop using your PG stuff ASAP....if your allergic reaction subsides then you'll know it's the PG, if it continues I would seek further medical help to avoid a serious problem.
Best of luck to you and feel better