Is it possible yes however 1 tend to turn into hundreds in very little time, just like there can be one adult and and eggs all over.
The best thing EVERY TIME you get a snake is to pre-treat the enclosure with Provent a mite, which take care of ALL STAGES of mites (eggs to adult) which other product or soapy water do not.
Now since you have identify that a mite was present and since you did not pre-treat upon arrival, I would highly recommend that you treat your entire collection as well to be safe.