Empty out the Bottle if it is still full of Lon Lon Milk by drinking the contents and then lift up one of the rocks near the pine tree. Otherwise, travel back to Hyrule Castle with your new Bottle. If you’re not interested in a full completion of the game or in obtaining all of the Gold Skulltulas (or coming back to complete this later) you can skip past this.
There is another Gold Skulltula that you can obtain when you enter the Lost Woods however you do have to go out of your way in order to obtain some bugs.