After having a leep of CIN 2-3, my latest pap smear says I have metaplastic squamous cells. What does that mean?

Benign process. Metaplasia is a reactive condition that occurs even in the normal cervix. The outer cervix (ectocervix) is composed of squamous cells, while the inner cervix (endocervix) is lined by glandular cells. In an inflamed environment, such as after a leep, glandular cells undergo metaplasia to squamous cells, as squamous cells are hardier.
Not Abnormal. A pap teat is a test for cervical cancer/precancer. Two common changes in cervix cells are metaplasia and dysplasia. Metaplasia is generally described as a process of cell growth or cell repair that is benign (not cancerous). It is usually just a sign that your cervix is repairing itself from the leep. Abnormal findings would have been persistant dysplasia or persistant hpv. Metaplasia is ok.
This is encouraging. These are cells that are transforming themselves into squamous cells, usually in response to some sort of irritation or in repair of previous damage. They are not cancerous or precancerous nor are they characteristic of an hpv infection.