Your throat swelling is nothing to be taken lightly. Try lower pg, and, if that does not help, see a doctor. My daughter gets the feeling that her throat is closing up when she has anything with artificial sweeteners, and wound up going to the emergency room once for it when she accidentally got a bottle of flavored water that had aspartame in it.
Quite a few vendors list pg first, then vg, but some do it the opposite, with vg listed first. If you are buying your eliquids at a store, double and triple check the label before you leave the store. If the pg/vg ratio is not stated on the label, ask the clerk. On special occasions, we treat ourselves to a premium eliquid that does not state the pg/vg ratios, but does list vg before pg in the ingredients, so this is a higher vg eliquid. If you are buying online, double and triple check the pg/vg ratios of what you are ordering. When in doubt, contact the vendor, explain your issue, and ask for help getting the correct pg/vg ratio for you.
As far as your custard issue goes, you might have burnt the coil, since vg is thicker and higher levels of vg require more wicking time. I have also found that, for me, custards/creams/some bakery flavors do not start to come into their own, flavorwise, until I have let them steep for at least 2 weeks. You might want to hold on to that custard, and try it again at a later date.
Be sure to shake the eliquid bottle every time you fill or top off your tank.