Some BPs get a little pink BEFORE they shed- I'm not aware of any that do afterwards, nor any that are "age-related".
What kind of heat are you using? UTH? Is it controlled by thermostat? What are the warmest temps. inside enclosure that your snake can touch if they push away the substrate? I am concerned that this is a "burn" from excessive heat. Can you post pics?
I may have misread your question, is the pink before or after the shed?