It's definitely NOT old shed skin...that appears to be a fungal infection...if you delay treatment, it will appear elsewhere on his body scales too. See your vet, they
can provide you with an easy-to-use-&-reptile-safe topical anti-fungal liquid medication to apply w/ Q tips. That should clear it up, & in time (after repeated sheds)
those scales should go back to normal-looking. (Years ago I had a BP that had this too.)