Improper Application
There are a lot of different kinds of sunscreen to choose from. There are many choices, ranging from how strong it is to how it is applied.
If you use a spray-on sunscreen, make sure your whole body is covered. If you don’t, you might end up with this. It looks like this person forgot to hold the spray bottle far enough away or rub it in well enough. To be fair, getting a sunburn makes it much easier to see what you’ve missed.
Asking for Help
Sunscreen only works if it is used often and completely. Most people cannot reach every part of their body, which is a shame. It’s especially hard to get to the middle of your back. That’s a lesson you’ve learned the hard way when you have an itch you can’t scratch! The next day, this person found out how far they could go when a patch of their skin that didn’t have sunscreen got sunburned.