We present the results of comprehensive time-dependent modeling of Mrk 421 in internal shock scenario using a MUlti-ZOne Radiation Feedback (MUZORF) scheme. MUZORF calculates blazar jet emission as a result of various radiative mechanisms, such as synchrotron, synchrotron self-Compton, and external Compton. It addresses the inhomogeneity in photon and particle populations in the region by slicing a cylindrical emission region into multiple zones and providing radiation feedback to adjacent zones. We have applied MUZORF separately to three spectral states of MRk 421 that were observed during a violent outburst in February 2010. Our results indicate that a particle population following a simple power-law and distributed in an inhomogeneous cylindrical emission region is capable of reproducing the spectral behavior of Mrk 421 in February 2010. However, departure from equipartition is required along with an emergence of a general trend, according to which the magnetic field strength declines and the particle population becomes energetic and harder as the flare evolves and attains its peak in the third and final spectral state.This research was supported in part by NASA through Fermi grant 80NSSC17K0650.