This is a Surly Krampus frame; I just noticed this small dent while cleaning. It was purchased brand new, I've had it for about 2 weeks. Should I be worried?
No, you should not be worried. A dent of that size is probably not a concern on all but the very lightest (and thinnest walled) steel tubing. Surly are economical bikes and use relatively heavy and thick-walled steel.
It’s my understanding that framebuilders can roll out dents larger than this, but not so large enough to warrant replacing the whole tube.