I was kinda bad and I did my first stretch not only jumping straight to 3mm (8g) but also with a plastic taper and left it in there for about 5 days while it was healing before replacing them with surgical steel plugs. Question is, my ears hurt throughout the day with the tapers and stopped hurting eventually and I replaced them with the steel plugs as soon as I got them from a shop that specialises in ear stretching. After one day I have had a swollen lymph node behind my ear lobe and I've been cleaning my ears about 2-3 times a day sea salt soaking. Is this an infection from the plastic tapers and it's only decided to kill it off just now?
I left my taper in too long and it began to heal but in a weird shape so i swapped to plugs and now its fine.. but you definitely shouldnt leave tapers in. I got some swollen bits on other piercings (not my stretched holes though) and it went down eventually. It may just be caused by the taper irritating an area or from sleeping on it weirdly but keep an eye on it and keep cleaning, if you notice puss or anything then I'd get it checked, or maybe go back to the shop and ask the owner for some advice on it
Keep cleaning it and if in a few days it doesn't get better, you should downsize. If there's any pus coming out of the stretch, then it's probably an infection. Take care!