Lemon juice does not repel mosquitoes.
I was told by someone to use some lemon juice on me to repel mosquitoes and it did nothing to repel the mosquitoes but it did attract ants to crawl on me while sleeping in the tent.
So it's not a good thing to put lemon juice on your body to repel mosquitoes because it does not work.
To repel mosquitoes you can use some Citronella or Tea Tree Oil.
The Mosquitoes hate the scent of Tea Tree Oil and Citronella and will avoid places where those scents are used.
If you're sitting outside you can also use an electric fan blowing on you to keep mosquitoes away from you as the wind from the fan will blow the mosquitoes away when they try to land on you or try to fly towards you.
I always use a fan outside on my patio when I'm sitting outside and trying to enjoy the evening and then mosquitoes come by.
After using a fan blowing on me the mosquitoes stay away from me and haven't bitten me since.
Also Lavender and Lemon eucalyptus oil are also good mosquito repellents.
My dad has a Mosquito magnet that uses propane to draw in and kill the mosquitoes and it works for him really good.
He said he's gonna buy me one of those propane mosquito magnets this month in a few days when his paycheck comes in.
They really do work and keep mosquitoes away.