My phone is touching in weird places

Hmm. That sounds like a digitizer problem. However, it could be software related, and it may go away after a factory reset.

Regardless, it is probably a good time to backup the stuff on your phone and try a factory reset.

There are a lot of ways to tackle this problem. The good news is that you have a One Plus 3, so you have control over your phone.

Option 1: Ask your question on XDA developers forum. That is the largest android community on the internet and you will probably get more detailed help. One plus has a good community on there too. Someone on XDA may have better solutions than mine.

Option 2: Boot to your bootloader and communicate to your phone via fastboot

you should be able to push some commands via fastboot to root your phone and then install a custom recovery. Once rooted, you can boot to recover. In recovery you can select factory reset and It will factory reset your phone. This will wipe all data on your phone so backup first.

Option 3: Troubleshoot through USB & ADB interface

You can communicate with your phone over usb when you have the correct USB and adb drivers installed on your computer. You will need to enable developer options on your phone, under settings, but if you cannot get into your phone(because of password and touch issue) this wont work.

Good luck!