25 Ways to Tighten Skin after #Weight Loss, number 19 : Castor Oil Castor oil is another great natural way to tighten up your skin. Weird right? But if you combine a little #castor oil with some lemon juice or even lavender oil and rub it into your skin, you'll see your skin start to tighten. To be honest, this is one of the greatest ways that you can tighten up your #skin! Only use a few tablespoons of castor oil every night and you'll see a difference!