Hi Trimom, you made a safe choice by my way of thinking. Anytime in the first year if you need to drain and refill to correct an installation problem you are safe to do so.

After that never drain.

Once the underside has dried out you could try setting the liner the way you did before. Fill at high noon, full sun and it might work. If that is what you did before you might try this.

With the pool assembled, pull the liner over the top rail and using many cloths pins, pin it to the top rail. Fill to two thirds full in full sun, then a couple of rails at a time, remove and set the liner and reinstall. Keep the skimmer and return attached, that was a good move on your part. Start pulling over the top rail close to the filter area but keep that area attached.

Hope that helps some, Dennis