Have a little lump on lower left leg with a discoloration on top of it. tender when i touch it. what is it?

Skin lump: There are many possibilities. You should see your doctor or a dermatologist to evaluate the lesion. The dermatologist will decide if a biopsy is needed to establish a definitive diagnosis. Treatment, if any is needed, will depend on what the diagnosis turns out to be.

Many possibilities: A lump under the skin could be as a result of different reasons of which could include an ingrown hair, lipoma, ganglion, abscess, or a tumor. Have it evaluated by your physician to get the appropriate treatment.