Welcome to the forum; thanks for your question.
I'm not surprised to hear that "The info on the Internet is confusing", There hasn't been much research on crab lice (crabs) or their transmission; most of what we know is based on clinical impressions, not systematic data.
That said, I am quite certain you don't have it. First, a massage parlor is an unlikely place to catch crabs, especially if they use fresh sheets and towels for each client (as you imply yourself). And even if they didn't do that, I would guess the transmission risk as very low, even if a recent client were infested. Second, a dermatologist is not likely to miss the lice or nits. Third, you would easily seem them yourself. You may have seen information on the web that they are hard to see. That's true, but it really applies only when someone hasn't looked carefully. On close inspection, they are always easily apparent. (If you are dark skinned, the lice themselves may be quite difficult to spot. But in that case, the nits typically stand out as white spots attached to the bases of pubic hairs.)
If your symptoms continue, I would advise you to return to the dermatologist for re-evaluaton. And if you want still further reassurance about crabs, you could purchase one of the over-the-counter treatments (e.g., Rid) and give it a try. But for the reasons above, I don't expect it would make any difference in your symptoms.
I hope this has helped. Best wishes-- HHH, MD
So If I gave myself close insepection I would be able to see the nits or crabs with my naked eye. Thanks for your help
Yes, you would see them easily.
Thank you for your prompt response , this is a great service I appreciate your help