Your skin is naturally covered in a natural layer of bark protecting your original form, want damage taken may reveal your skin underneath but upon healing or resting the bark seals hiding it again. Any armour worn will slowly be consumed and covered as well, just like a tree growing and consuming anything stuck in it 

This gives you resistance against bludgeoning, and a weakness to fire.

Nymphs don’t need to sleep. Instead, they meditate deeply, remaining semiconscious, for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep. Magic cannot put you to sleep. In addition, you do not need to eat, though you require more water than an average humanoid

Due to your soul becoming one with nature and fey magic, you have gained the ability to control, destroy,  you gain the Wood manipulation (Home brew) cantrip.

Due to your fusion with nature and fey magic, you can speak, read and write Sylvan, common. You can commune with nature. However, in your past life, you had a different language native to your homeland. This language is buried in your soul giving you the ability to read, write, and speak 1 other language of your choice.

Due to your soul now being infused with fey magic, you are naturally beautiful, adding plus 2 to your charisma and a +1 wisdom ability scores