Yes this is serious issue.
After any dislocation, the joint had to be immobilised for 4-6 weeks.
Knee is a major weight bearing joint thus 6 weeks immobilisation is for sure. You can do static quadriceps exercises though. Apply local ice packs.
Next Steps
You should undergo x-rays and MRI for sure (100%) to check on the damage of knee structures.
Health Tips
Do not move injured limb or bear weight.
Take second opinion as you situation looked neglected .