You can easily control the problem with melisma (condition where dark color patches or discoloration) with a mixture made of lemon juice and onion juice. You should just clear the area where you want to apply the mixture and after that with the help of cotton swab to apply it. Be careful around the eyes while applying. You should leave it like that for around 20 minutes so it can act and after that with warm water to wash it off.
Onion juice can be as well be used as skin tonic. All you have to do is to prepare mixture out of 1 yolk, 1 tablespoon of carrot juice, 1 tablespoon of olive oil, 1 tablespoon of rose water and 1 tablespoon of onion juice. You should mix all these ingredients in a bowl. Clean your face well and after that again with the help of cotton swab apply the mixture. Wait 20 minutes before washing it off with warm water. Do this at least 3 times in a week and your skin will be healthy and lighter.
But that is not all. You can use onion juice in the cases with moles. With a cotton swab, apply fresh onion juice on the moles and leave it like that for half an hour. Do it 3 times each day for a couple of weeks and your moles will be gone.