To most people this material is known by the brand name Teflon. This material has been tested and when it meets the requirements of the standard ASTM F754 it is an implant grade material that has been found suitable for use inside the body. So if you want plastic jewelry, make sure it meets this standard.
A disadvantage of this material is that it is quite soft and easily damaged and the surface is often not very smooth. This can cause a lot of irritation and can give bacteria the chance to settle in the jewelry and cause inflammation.
PTFE is therefore more suitable for short-term wear in the body when, for example, a medical examination has to take place which requires you to remove all metal jewellery. The metal jewelry is exchanged for a PTFE variant that keeps the hole open. After the examination, you can switch back again, so you do not have to worry that the hole has closed during the examination.