Small amount of blood post chip is fine, just everytime u go to the vets ensure they check its position just incase it migrates to a different spot, can happen....not often though!
Small amount of blood in faeces can be a couple of things, first one i would guess is over straining which may produce a little fresh blood as he finishes his "deposit"!
The 2nd a little intestinal irritation which can have many causes inc stress, the gut lining becomes a little inflamed and bleeds slightly which would result in runny dark very smelly "deposit" and pup would go frequently often only producing small amounts.
As long as not being sick i wouldnt worry too much at this stage, leave it a couple of days and if still the same back to vet.