What Causes Bulkiness And Discolouration Post Mesh Replacement Below Naval Cavity?

Hi doc,my mom went trough mesh replacement and the 10 inch long parallel incision is just below the naval cavity... now just near to that she is feeling a portion getting harder and after 10 days it is turning blue and blackish.. but no pain no fever... coz she is bulky her wound recovery is also slow..please give info what is that hard portion and why is turning blue and black and harder and treatment..