Sometimes they just get abnormal looking quills that are curved, weird-shaped, flat, etc. Usually they're not a problem, but try and keep an eye on it anyway - sometimes they can turn into ingrown quills that need to be pulled out in order to let the area heal up. You can go to the vet for that if you're not comfortable doing it yourself. I went to the vet for the two main ingrown quills I remember Lily having, as I didn't feel completely comfortable removing them myself. Another member just had an issue like this though, and pulled it out herself with tweezers, with the quill coming out easily. Afterwards you can put a little plain Neosporin/Polysporin (not extra strength or pain relief) on it if you want and continue to keep an eye on it until it heals (or make a vet appt if it doesn't looks worse, obviously). Good luck, and I hope it turns out to be no problem!