There are many stages in between, but these are approximately 2-3 weeks after you've initially been bit.
The mites aren't visible to the naked eye and until you realize something's itchy like a mosquito-bite you won't see a bite mark or raised skin.
It will begin though looking very much like a chigger-bite
Before even that and until you work through all the B.S. and find a good Dr. and DO know what to look for, they'll look very much like a teeny-tiny, pin-prick red dot. Like a hemming-pin.