Lumia 930 dropped in bath, turns on now, but does weird things.

@eximpo, sounds like you got your work cut out for you. First off, "placed in bag of rice for 3 days." does not do anything. It is a myth, and nothing but a myth. Rice is only good for cooking and has no place in electronics repair. Using rice is the equivalent of not doing anything. It's a waste of good rice.

What you want to do is to totally disassemble your phone and clean it with 90%+ isopropyl alcohol and a small brush. Check to see if this video will be helpful to you. Remove all EMI shields to do so. Use this guide to help you with that. It was written for an iPhone but all the steps are pertinent to your phone as well. You must clean all connectors and all flex cables. While you are cleaning it, checking your circuit board for any missing or burned components.

If you do not clean your phone, you cannot properly troubleshoot it. Any part may have failed due to water damage, and the longer you wait further parts may fail due to corrosion. It will continue to fail until it will be totally destroyed.

Yes, it is possible that it is your digitizer that is causing this, but it is also possible that this is caused by shorted out digitizer circuits or the IC itself.