Took nose stud out after 6mo & there's a bump

I got my left and right nostrils pierced at the same time. Right healed fine, left always hurt a little if I twisted it or messed with it too much, but I figured, "Eh, just don't mess with it." It always felt a little snug compared to the right. They were pierced with titanium threadless posts.

Today, I took it out for the first time due to surgery and there's a bump inside my nose! It doesn't hurt unless I push on the outside of my nostril (and even then, hurt is too strong a word).

I was thinking about buying a longer threadless post, but is there anything else I need to do? How do I know if it was too long or too short? Should I put it back in? Leave it out? It'll take a few weeks for the delivery.

Unfortunately, I am disabled and recovering from my surgery, so I am unable to make it to a piercer and I don't have any piercer friends :(