Big toe is red. very tender &painful. only painful below nail bed. can feel a lump a little before the nail bed. what to do and what could it be?

Probably ingrown....: There is a small piece of nail still embedded in the corner. You need to get that out. Soak to soften the area and try to get it free. If you can't get it out on your own, a podiatrist can. Sometimes this can be done without numbing the toe, but often, anesthesia is necessary. If it is a chronic condition, there is a very successful surgery that can be done to permanently correct the problem.

Red toe: It sounds like your toe is infected.And needs treatment. See your doctor or a podiatrist for help.

Overgrowth: Could be a callus or a bony or cartilaginous overgrowth. Have an x-ray taken to evaluate the bone underlying the nail.