I fell of my mountain bike and had a large thigh hematoma, other than rice, what should I do?

Seek evaluation. Initially, r.I.C.E. Is indicated to minimize the extent of bleeding and damage in the muscle. After the initial inflammatory phase resolves, early passive and active range of motion exercises and a guided physical therapy program may help hasten recovery. Formal medical evaluation is recommended to determine if drainage of the hematoma is necessary or if an injection can be beneficial.
See below. For a moderate size(expanded) after three or four days of gentle heath do nothing. Body will clear it in 8 to 10 weeks. If hematoma is big and not large(expanded) need to be evacuated by a physician, other wise may cause permanent scaring in the tissue.
Stretch. A thigh hematoma will resolve with time. Ice for 20 minutes at a time, no longer, for the first 3 days, 2-3 times a day. Stretch gently and be sure that you are able to progressively increase the amount of flexion (bending) at your knee and focus on walking heel to toe! the primary concern with this injury is loss of motion so if that does not seem to be improving see a therapist.
Yes. Compression of the hematoma may help in dissipation. Aspiration is rarely indicated. Rest is important and ice in the early stages. Premature application of heat can increase bleeding and thus the size of the hematoma.