How do I fix my phone if it was in the washing maching?

Take it appart and clean the Board with much alkohol, and i mean MUCH. If you have the chance you can clean the Board in an ultrasonic bath, but be aware that this can destroy the position sensor.

After that i would look for signes for corrosion or shortages. If the board looks good after the cleaning you can try to turn it on.

If it dosent turn on you have to track why. Test a new screen on it, chek if the board has power and so on….