Slight discomfort in the knee

Hello

I started yoga recently. After class today, my knee has had a slight discomfort, it feels a little tight or a little swollen. I was a serious dancer my whole life until I stopped two years ago. I am very flexible and can easily do most of the poses. I have never found lotus difficult. Today I tried bound lotus, and put my head to the floor in this position. I did not experience any pain afterwards. However after the class I have has this “swelling” feeling in my right knee. It is not painful, I can still do everything, however it feels a bit uncomfortable. I do have a hyperextended knee, that bends backwards when I stand. I am quite tall and of medium build. Do you know if this could be a serious new injury? I have tried to google information and have become increasingly worried that I may have injured my knee. Does anyone know? Is there anything I can do now?

I would stop asanas and seek expert advive on your knee.
I had slight discomfort about 6 months ago yet stupidly soldierd on - 40 months ago seeked help, strained knee ligaments and small tear meniscus. Have practised asanas for 20yrs with no problems, never had knee problems.
Lessons i learnt - listen to your body - it doesnt lie, and treat knee shoulder discomfort as injury and seek help.
I had have 15 weeks off asana yoga practise and 16 weeks out of surf.
Dont take knees for granted - seek expert advice