Can I use kojic acid before putting retin a (tretinoin) in my face to make it lighter?

Depends. Either alone may not irritate your face, but you may not be able to tolerate the combination. I would suggest that you try a spot under your chin for a few days to find out if it would be ok to use it on the rest of your face. Whether you get peeling and irritation also depends on the concentration of the products.