Is it too much?

so like should I yse both urea and amalactin or is it better to stick to one overall?btw my skin is alr pretty used to amalactin so adding a 20% urea cream I don't think should be a big deal right?and if yes,then how?(lmao why is it so difficult)should I put layer them or put one in the morning and one at night or alternate between them?