First year here- I felt the same way when I was waitlisted! I was waitlisted mid-April last year, and I sent in a LOI at the beginning of May, and was accepted a few weeks later! So I don't think it can hurt.
This is what Brenda told me last year:
You may address your letter to either Dr. John A. Paraskos, Dean for Admissions OR to the Admissions Committee. It may be sent electronically to me OR the admissions email (
[email protected]), faxed (508-856-3629) or to the following address:
UMass Medical School
Office of School Admissions
Room S1-112
55 Lake Avenue North
Worcester, MA 01655