How likely will a second ptosis surgery work if the first didn't and will the extra crease go away? (Photos)

You should wait 6 months before doing anything. It looks like you had an external approach the first time. On the lower side you do have a low secondary crease. Since you want to tighten the lid crease to eliminate the lower one, you would need to go through the external approach. So it would be easiest to tighten the levator when doing that. Alternatively you could have a mullerectomy to lift the lid (need to do a neosynephrine test in your doctor's office to check how much to correct) and then just tighten the skin on the outside.