First of all, nobody held a gun to your head. You did the work voluntarily so if you got hurt that's on you.

Frankly, you should have read your lease contract before agreeing to pay for any repairs to the landlord's property.

You would have likely found that you have no responsibility for repairs to plumbing, fixtures and equipment due to wear and tear or malfunction through no fault of your own.

You should also read the Arizona Residential Landlord Tenant Act, Chapter 10:

http://www.keytlaw.com/azlandlordten...nd-tenant-act/

Even now you might be able to recover the money you paid for the repairs that the landlord should have made.

But, sorry, nothing for the injury. Had you known better, you should have just refused to handle or pay for the repairs. Unfortunate that you succumbed to some jerk yelling at you.