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.

After surgery, if there is anything amiss, always check with your surgeon.  That said, no pain is good.  You may just be feeing the top part of the implant as the gum heals and shrinks down to it's final form.  It is not dangerous.  However it does deserve a consult with your implant dentist to really tell you and to take away all your worry.