Hi, @Lauren Moore - welcome to the Community!
This is due to a change that Atlassian has rolled out recently. The intention to do so was documented here starting last year. (I assume you mean that it's been replaced by the Summary field, not the Description, which is the formattable text field.) Not everyone is thrilled about it; note the 9 pages of comments.
Short answer is, no - you can't revert the change. What you can do is run an automation rule to copy your epic name into the summary field.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.