Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.

Doing a plastic surgery to remove excess skin is permissible because there is an emotional and physical pain you are suffering from. According to the report of Arfajah, he said, “My nose was severed on the Day of Al-Kulab during pre-Islamic period of heathendom. So I got a nose of silver which caused an infection for me, so the Messenger of Allah (peace be upon him) ordered me to get a nose made of gold.”

It is well known that he could live without the outside part of the nose, but he wanted to regain his original shape. He fixed this golden nose to seem normal.

For `Isha’ prayer, its time continues up to the break of true dawn. You can pray without intending it as a make up. It is, however, a time for those who have a necessity or a pressing need. You are recommended to pray `Isha’ before going to bed because the Prophet disliked sleeping before the observance of `Isha’.

Almighty Allah knows best.