Go see a sports Chiro with a CCSP diplomate. There's a reason why these guys take a leading role at the Olympics, because they know their shit.
Everyone's advice is great and all but it's like shooting fish in a barrel.
First of all going balls to the wall training in something you haven't done for awhile or something new can and will always increase your chances of injury. So remember to always ease into things.
Giving advice without seeing the person in patient is near impossible. There are 10 more questions that someone would want to ask before they should even consider giving an opinion. First of all we don't even know his/her age. There's a big difference between someone 20 vs someone 50.
When you say inside of your knee, that could be like 5 different spots which all have different mechanisms of injury, and treatment plans. Keep in mind that one treatment plan will most likely aggravate the area more if it's not the right one.
Go see someone now before it gets worse, and dont take some half ass answer from some schmuck, be informed and investigate the doctor before you see them. MRIs are often warranted for knee problems.
Go see someone now.