Hi..you would require a operculectomy or wisdom tooth removal to solve this problem. Regards

From your complaint it looks like mostly you have your wisdom tooth which is erupting & that's the reason for your pain on eating & drinking. what I suggest is do some warm water gargles & take one tab combiflam for now only once.  do warm salt water gargles 3-4 times a day.  if it doesn't subside in 2-3days visit a dentist.  ideally you should visit a dentist soon but tomm being Sunday you can do this now & if it doesn't help visit one of Monday & get an xray done.

Dear Ashay, let me first congratulate you for being so alert and observing your mouth carefully. Now comming to your problem, as you have explained there are few possible reasons for it as follows :- 1.  - You must be having an erupting Third Molar ( Wisdom Tooth)  which is partially erupted and overlying gums have been hurt while brushing.            To treat this case we need to investigate the area you marked with X-Ray so as to confirm weather wisdom tooth is present or not, if it's there we have to analyze weather it's in proper position to erupt/ come in mouth or not. If tooth is in  proper direction and having sufficient space to come in,  we need to do a minor sirgical procedure called "operculectomy" in which we cut the gums covering the tooth.     But if there is any problem in the tooth as above mentioned we may have to extract / take out the tooth. 2. -  Second possibility is that you must be having some plaque or tartar accumulated around your last teeth in particular area,  which is causing the problem.   In this case you may be suggested a simple teeth cleaning procedure called scaling and polishing. 3.  -  Third possibility which to my opinion is least possible in your case is,  may be you must have some cavity/ caries being developed between your last molars. This can be detected on X- Ray itself. 4. -  Last possibility is that as you mentioned because of rough brushing techniques,  you might have hurt your gums.         But in this case too I will sugest you to visit nearby Dental Surgeon and consult him to rule out other possibilities and to know more about "PROPER BRUSHING TECHNIQUES ". Good Luck

That is most likely pericoronitis . warm saline rinses and betadine mouth rinse