In Compton effect in energy conservation equation why don't we consider potential energy of electron due to neutron?

Dear student 

When electrons and photons collide, there is indeed inelastic collision. As niels had mentioned about Compton scattering, I will elaborate more. During Compton scattering, the photon loses energy, part of which is transferred to the electron. However, Compton scattering is a mid-energy phenomena of light-matter interaction. If you are looking for high-energy interactions, you need to read up on pair production, where a photon splits into a positron and electron due to high energies.