Has the snake started the shed process itself? If not, you should not be doing anything until it starts. No matter how bad the shed might be you should be able to see signs of it beginning.
If your snake has started the shed process and it's flaky and coming off in patches I suggest you do nothing physically to the snake. Boost your humidity and keep it right. To help with this get moss and put it the hides. Keep it moist until the snake sheds. After you get a complete shed you can allow it to dry out before making it damp again. Then when you see the first signs of shed make it damp again and keep it that way until you get a shed.
Accurite thermometer/humidity combo gauge can be had on Amazon and at Walmart for about $12. It has a wired probe for the hotspot and then the unit will read the ambient temp and humidity.