Can I use dermoplast spray on tummy tuck incision for pain and itching? How do you prevent infection?

If your incision is opened then you have a wound and should consult your PS about wound care which is generally packing with saline gauze.  But you should consult with your PS first.

Thanks for the question and hope you had a great holiday.  I recommend asking your surgeon as the details of your surgery can make a difference.  If you had a surgical glue or tape applied to your skin, then you don't need to apply anything until those come off.  If you have a closed incision, generally nothing is needed other than washing with soap and water after you have been cleared by your surgeon.  If you have developed an open wound, then you should follow your surgeon's recommendation on cleaning the wound and what kind of dressing to use.  Basically, your surgeon knows the details of your surgery and would be most knowledgeable about what to do in your particular case.