بسم الله الرحمن الرحيم
After being free from Nifas (postnatal bleeding) if you feel pain by pouring water over the wound or fear that your pain may increase then put some cloth or cotton over that part of wound and wash the other part of the body and do masah over the places that is covered with cloth and if it is also not possible to pour water like this then do tayammum and offer salah.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.