Go in, tell them you can't work & fill out the report.
If you don't have it looked at & assessed proper care, you could wind up with a life-long crippling injury & you're WAY too young for that.
It happened at work so you need to fill out an incident report because it covers THEIR ass as well as yours.
And if you continue to be stubborn about it, they may decide NOT to keep you because you WILL become a liability.
This is part of that 'grown up stuff' you learn to deal with.