I have a teensy tiny shard of glass stuck in my toe. I tried to get it out but couldn't. Advice?

See Podiatrist. You need a proffesional to remove glass and treat appropriately.
See PCP. A small spec of glass causes a foreign body reaction and can give increased sensitization to that area. Glass may not show up on x-ray, ultrasound or other imaging. Often, it will "work it's way out" and you will be rid of it. If not, your pcp, surgeon or other medical professional may have to explore the area under a local anesthetic and attempt to remove the foreign body.