My 18mos old has a small thorn in his heal and i can not get it out with tweezers. what should i do? will it come out on its own?

Foreign body: Tiny foreign bodies that are embedded in the skin will generally dissolve or extrude on their own with time, providing they are organic in nature (plant material vs. glass). Excessive attempts at remove can increase inflammation, pain and infection risk. Local wound care and close observation is usually all that is needed in the interim.