The information you have provided is not very specific; a lump on the toe could be caused by a number of reasons such as an infection, sebaceous cyst, varicose vein, malignancy, skin cancer, fracture, haematoma, ganglion, callus formation, scar tissue, ruptured Achilles heel, lymphadenopathy, or it could also be a simple toe injury. However, your symptoms sound a lot like a blister...