My 2 year old son has a hard lump on the palm of his hand just under his third finger. it doesnt bother him. any idea what it could be?

Doctor can examine: A toddler with a small, firm skin lump on his palm near the base of one of his fingers can have his pediatrician take a look to decide what it might be. In an older child who plays on playground monkey bars, the likely diagnosis is a callus. In toddlers, a skin bump there may be a reaction to a tiny splinter, a small wart, molluscum, etc,... Usually, an in-person exam can figure it out.