How long should it take for me to get a constant read on the xSIID implant?

I was able to read it within like two days of installation like once or twice. It’s been a week and the light on it gets pretty bright but I can’t seem to pick it up with my nfc tools app anymore and I never got a constant read on it in the first place.

Not uncommon, straight after install there is little inflamation, then when the swelling comes in, you will likely struggle to get a read like you are now.
Give it a couple of weeks and you will be Rick Rolling people left right and centre