Ok here is what i did, i made some changes and saved to a esp file, but i did so many things and now i dont like some, how do i restore lets say... a default race i edited? obviously i could just start all over, but i rather not cause i like some of the changes i did, so if i just want to restore a Race, NPC or Setting to default should i just delete it? it wont affect the stability of Skyrim? if anyone knows a trick please let me know, i am kinda new to all this.

Help please and thanks in advance.

unless you've got a backup i dont think you can, once its saved and you've exited out of the editor thats it

You can use the Details button in the File/Data menu to Delete everything you don't want in your mod.

Much more comfortable are TESVSnip and SkyEdit, the later even more so, but it can't handle all record types yet.

Thanks alot!