As someone else with pewters, I have to admit . . . I see no pewter there. I see the pastel gene for sure but in the last two photos, the snake has the look of being in some stage of shed to me. Granted, I could be wrong, but it sure looks that way on this monitor. Pastels look atrocious in shed, so if this guy is indeed in blue, that alone will make ID trickier. If it is, trying to ID it might be easier after it sloughs.