I am typing in the permsission to give myself acces to admin on the skipnight plugin but it says the permission doesnt exist. Also there is no voteday option when nighttime comes. Not sure what is happened as I did not touch anything on the config or json files. 

Any help would be great

it always better to attach a copy of your  config,
Here  is mine and is working ok, You have made yourself admin ? and used
/oxide.grant user <user name>skipnightui.admin

{
  "Messaging": {
    "DisplayCountEvery": 30,
    "MainColor": "<color=orange>",
    "MSGColor": "<color=#939393>"
  },
  "Options": {
    "RequiredVotePercentage": 0.4,
    "TimeToOpen": "19:00:00",
    "TimeToSet": "09:00:00"
  },
  "VoteTimers": {
    "TimeBetweenVotes": 5,
    "VoteOpenTimer": 4
  }
}​

Make sure the plugin is in your plugin folder in oxide. Sounds like it's not loaded .....