I'm not on the lease but listed as a resident?

I moved into a place with 2 girls into a badly kept room. I guess I umed it was a pretty laid back situation because of the condition of the house. I did no walk through with the land lord. It turns out it was not a good idea. There was a giant scratch that extended the whole of the room on the wood floor, and there were 30+ nails and holes in the wall when I moved in. I put up a small 1 foot by 1 1/2 foot shelf up and there were probably some small scratches in the floor from just normal living. I paid a security deposit as a courtesy to the landlord because she wanted to make sure I was invested in taking good care of the house which I did. She now is trying to charge me for $450 worth of damages over my security deposit because of the shelf I put up in the already nail and hole ridden wall because she wants to have the walls completely redone, and she also wants to charge me to have the wooden floors completely re-done which knocks out the original security of 415 dollars. Like I said, I am not a signer of the lease but I am listed as an other resident. Can she legally be trying to collect for these things? Can she legally be withholding my entire security? I live in Oregon.