Toothache leading to Gum Swelling

Hi! Let me give you a history of my fianceè's tooth/gum swelling. He complained that his tooth was aching, I guess it started in the middle of October or early November. He was self-medicating and took amoxicilling once a day for 6 days only. Then a few days ago he started complaining about the toothache again on the same area. Before we went to bed, he took one capsule of mefenamic acid. Although the pain was temp relieved, it started kicking in again a few hours later interrupting his sleep. Eventually, his gum started to swell and his right cheek was puffy. So we went to visit the dentist and assessed his tooth. The pain to be exact is at the right side, lower part of his mouth. Now the dentist suspected he was having a third molar erruption but he wanted to make sure so he requested an xray andpresc him w/ Lincomycin Hcl (15 in qty) every 8 hours. So technically that was only good for 5 days and we were informed that this type of antibiotic has a stronger effect. Take note: we were not informed if we are to come back at the clinic or not, should the swelling subside or not. Anyway, my fianceè obediently took the antibiotics for 5 days. He questioned the dentist why he's only taking it for 5 days. I mean we both knew that antibiotics are taken for at least for 7 days.

The dentist said it was fine so we weren't really thinking about it since doctors knows best. After taking the antibiotics, we missed to visit his clinic yestrday because we had so.many things to do at home. Knowing that my the swell was almost gone (although when you touch or palpate his right lower cheeks, you can still feel the minimal.swell left) and the pain gone, so he can do his regular activities. We visited the dr just a few hours ago to seek advice after taking the presc med. But I was upset that he informs us we should've gone to the clnic bec antibiotics shouls not be stopped since he can still add up additional two more days for the same prec. I was confuses bec he could've given the presc good for 7 days the first time we were there, I mean what diff does it make? So now he would have to start another type of antibiotic since the chances are the bacteria is resistant to lincomycin. I wanted to ask if it's alright for him to take another set of antibiotics and will thataffect his liver or kidneys? Was the dentist wrong about presc lincomycin good for 5 days? And to add up, there was no visible tooth on my fianceè's gum. We don't see any tooth errupting either and he has no cavity in that area, the gums has no flaps and the swell is not found on the gum where the wisdom tooth should have been. I hope I'm making sense. Hoping for your response