Should I retake a 35 ACT if I got a 33 in science?

You can retake the section test in September, but you will need to get a 36 in science to get a superscored composite of 36. Not all schools superscore, nor do we know how schools will treat these new section scores.

I would definitely not retake a full test. Maybe take the section test in the fall if you have schools on your list that superscore. What schools are you targeting?