Hamstring tendon - what happened?

So im a very serious gymgoer and train since 8 years.

I did an exercise called hyperextensions at the end of my workout and had my legs all stretched out during that exercise.

after my set, I got up and felt a stabbing pain in my leg. I recognised that pain when i was standing and stretched my left hamstring, i would feel the pain then, otherwise no recognisable painful feeling.

Walking home was possible and stuff, and since then I feel the hamstring 'flaring' up, in a burning fashion.

i cant exactly tell what it is, muscle or tendon, but when I use the muscle at weight training, along the inner part of my hamstring i would feel this burning, scratchy kindof feeling.

Doctor said to just stop training and itll be alright.

Its now been 2 and a half weeks since that accident and it still flares up like day 1.

During the exercise i could not feel a snapping or ripping feeling/sound so I cant tell if tendon or muscle is torn. I literally just had this -> do set, finish last reps, get out of hyperextensions machine, stand, boom. stabbing/pinching pain (bear in mind its not something that was very painful. just a "stretch it further and its really going to hurt"- stabbing pain.

Its now gone obviously except for the burning pain that flares up most of the time I use the hamstring a lot (not talkint about jogging or so, but if i have some resistance on it).

What can all the possibilties of my 'injury' be?

It takes so long until my next doctors appointment and I am very curious as i actually wanted to weightlift competitively in summer

kind regards

I marked this picture in red, so you can see where the pain flares up (note, its not always the whole red line, sometimes its just the part near the knee, sometimes its more near the glutes, but almost never the whole line. It switches somehow, but mostly front part at knee)