A bedhead is a messy hairstyle introduced in City Folk. A bedhead only occurs if the player has not played for 15 days. The only way to remove a bedhead is to go to Shampoodle, a hair salon in the city, or on Main Street in New Leaf, and get a new haircut for 3,000 Bells. Bedhead can be hidden with a hat, wig, or Mii Mask, though some hats do not cover all hair. Some hats can cover all of the player's bedhead, e.g. hero's hat. Bedhead can happen regardless of hair color or style.
If the player chooses to keep bedhead, villagers may sometime comment on the player's messy hair, though only snooty villagers seem to dislike it, and will pass judgement on the player. When the player first talks to a villager, they will comment on the player's messy hair, regardless of whether or not the hair is covered. However, after that they will no longer mention it. Gracie will refuse to give fashion advice if the player has bedhead.
Tip:wearing your mii head before leaving for a long period will keep your hair in good condition-JJgamer86