C# graphics draws behind Panel

Im in winforms and trying to make a tileengine in it for school reasons. I have a trouble with drawing the tileset in the Panel. It's instead drawing in the top left of the Form and behind the Panel.

This is the code:

private void gfxPanel_Paint(object sender, PaintEventArgs e)
        {
            using (Bitmap sourceBmp = new Bitmap("../../assets/art/Tileset5.png"))
            {
                Size s = new Size(level.TileWidth, level.TileHeight);
                Rectangle destRect = new Rectangle(Point.Empty, s);

                for (int row = 0; row <= level.MapHeight; row++)
                    for (int col = 0; col < level.MapWidth; col++)
                    {
                        PictureBox p = new PictureBox();
                        p.Size = s;
                        Point loc = new Point(level.TileWidth * col, level.TileHeight * row);
                        Rectangle srcRect = new Rectangle(loc, s);
                        Bitmap tile = new Bitmap(level.TileWidth, level.TileHeight);
                        Graphics G = Graphics.FromImage(tile);
                        G.DrawImage(sourceBmp, destRect, srcRect, GraphicsUnit.Pixel);
                        p.Image = tile;
                        p.Location = loc;
                        this.Controls.Add(p);
                    }
            }
        }

Whats going on here and what am I doing wrong?