When you apply the Cosmelan Part 1 mask it stays on for about 8 hours and is a yellowish-brown color, so there is no way you want to go out and about with it on. The next 24-48 hours after you will be red and even peely. Most of my patients do Cosmelan on a Thursday or Friday and return to work on Monday, with make-up on. This would be the same timesframe you have planned. So as long as you are good to put on make-up over any redness, your timeframe seems just fine.
"This answer has been solicited without seeing this patient and cannot be held as true medical advice, but only opinion. Seek in-person treatment with a trained medical professional for appropriate care."