My Mom Had Total Knee Replacement 4 Weeks Ago. She

My mom had total knee replacement 4 weeks ago. She was on Warfarin, she discontinued it before surgery and was given lovaxin injections and heprin. We think during injections a muscle tore causing a bleed and hematoma. She had to have 4 units of blood and previously frozen plasma. After rehab in a rehab facility, her cardiologist has put her back on Warfarin. Today is her second or third dose, she complained of being weak and dizzy. Could she be bleeding again?