How much time should one allow after a dermabrasion if going on vacation where there will be very strong sun exposure?

Dermabrasion is a procedure which mechanically removes a portion of the skin (epidermis and the upper dermis) as a way of stimulating new skin growth in cases of scarring or sun damage. For example skin that is scarred from old acne can be improved once healing is complete after dermabrasion. But this sanded skin is very sensitive in the days and  even a couple of weeks afterwards. Sun protection is vital during this time to avoid burns and excess pigmentation. 

That's a great and important question!
As microdermabrasions exfoliate your skin, your skin is more sensitive after treatment. Therefore, you have to take special precautions. I would wait at least 3 weeks post dermabrasion to be exposed to the sun and make sure you apply an SPF every day that has at least 7.5% zinc.
Best,
Dr. K