Replaced Screen, works, but goes into boot loop, fixed by taking apart

Patryk, water is water...it is conductive even if it's medicated water for the ears. You need to clean out as much of it as possible, either on your own or via a professional shop. The sooner you do this the better.

The water is inside the phone, on the logic board and under the shields, even under the IC's. The real problem is the corrosion that is taking place as the water evaporates. Powering on the phone accelerates the process.

Here's what you can try yourself:

• Open your phone and remove the logic board (follow this guide)
• Inspect the logic board, especially around the connectors and look for corrosion.
• Inspect both sides of the board. Unfortunately, 80% of the board is covered in shields. That's usually where the damage is occurring.
• Put your board in a container with >90% isopropyl alcohol and let it sit for a while.
• Use a soft brush, like a toothbrush and lightly brush away any corrosion you see.
• Rinse in alcohol and repeat.
• Let it air dry for a day.
• Re-assemble and hope for the best.

UPDATE (03/16/2017)

Did you clean as I suggested? Did you notice any areas that had been contaminated with water? Based on your updated comments, it appears as though there is a problem on your logic board. There must be some corrosion, visible or not, that is causing an intermittent connection.

A professional repair shop that does water damage repair may be able to save your phone because they have access to pro-level ultrasonic baths and specialized cleaners.