I had 4 upper implants 2 weeks ago and tonight can feel a small bit of metal in gum. Should I be worried? No pain

This is normal after implant surgery.  The metal healing collars extend through the gums usually and remain there throughout the healing phase.  This way the surgeon does not need to cut through the gums a second time.

Don't worry. This may just be the cover screw or healing abutment peaking through the gums once he post surgical inflammation starts to subside. In my experience this is rarely a problem. 

You might be feeling the margin of the implant or the healing abutment. It is best to ask the surgeon who placed the implants and they will clarify which it is.