I have prostate cancer metastasize to the bone,  taking chemo tx.  My gums and teeth are very sore and painful....This weekend I developed a lump under my chin.......about a year ago I fell and landed on my chin......I thought I might have broken or chipped a bone at the time......It healed.  Now this lump has me worried.....Wonder if its cancer?
The first line treatment for stage 4 prostate cancer is not chemotherapy but hormone therapy (unless you have already received it). This comprises a small surgery to remove the testicles (the source of testosterone which stimulates the cancer) followed by Tab Bicalutamide 50 mg daily till response lasts. Response is assessed by monthly serum PSA estimation. So consult your oncologist about this. As to the lump you shouldn't be worried about it as it most likely the result of trauma than anything else.