Write a reminder about a possible undergraduate project
I'm not in the best position to advise you, but, perhaps, he/she hasn't answered you back, because he/she was busy to do so.

Thus, you definitely should e-mail back. Quoting a professor, maybe something like this:

"My e-mail server has been acting up lately, so I'm not sure whether my previous message was delivered properly; here it is again, just in case. Thank you!"

Read the following before:


Email Writing Tips
Read This Before Cold-Emailing Me
Examples of Good and Bad Cold Emails


Best of luck!