I self implanted an xLED in my left hand, between my pointer and thumb in 2020. I tented the skin and did my best to implant in the correct position. I haven’t had many issues, until recently- Occasionally I would get a “cramp” in my hand around the chip, but it would usually resolve itself after stretching out my hand. Recently however, I’ve noticed that there’s a vein running parallel to the chip, either right under or over it (My guess is underneath?) Whenever my arm is in certain positions such as down by my side or bent 90° with weight on my elbow, I notice a sharp pressure where the chip is located. I’m concerned about the possibility of the chip somehow ending up in my vein, and migrating causing a worst case scenario (pulmonary embolism). Does anyone have any experience with this and have any advice? If need be, I will get the chip removed, though I’m not sure if my doctor would be willing to perform the procedure.
I’m not really knowledgeable enough to give any advice, but implants traveling veins has been discussed at least once:
I saw that post, that case is primarily the reason I’m concerned just knowing it can happen. 
I haven’t had any issues until recently, almost 4 years later whereas his implant was done a few days prior.
The only way for it to get into a vein would be if it was injected into it or was hanging halfway in the vein and finally slipped in… but this would happen pretty darn fast, not take years.
The only other way would be that the glass fractured and cut it’s way into the vein.
There’s no way for there to be a functional chip without any damage to migrate into a vein on its own. You’d need a sharp edge to cut into the vein. This is why it’s so hard to get a needle into a vein to draw blood… it’s not easy.
I think there would be a hematoma or some bruising that works occur if that was the case no?
Yes one would assume