Mistakenly deleted custom entity from UNmanaged solution

I mistakenly deleted a custom entity from our main unmanaged solution in our Dev Environment.

That solution was previously imported as a managed solution in our Production Environment.

Now, I want to recreate it in our unmanaged solution. But I thought I'd need to get rid of it in our Production Environment.

I can't delete it since it is managed.

Also, if I import the Managed solution without the custom entity, the said entity is still part of the CRM...

Any advice?