Molly

Does the white spots mean there's something wrong it her?

yes

What can I do to get rid of it

It could be caused by poor water quality or a protozoan infection.

How hard is the water (GH) and what is the pH?

How often do you do water changes and how much water do you change?
How often do you do gravel cleans?

How often do you clean the filter and how do you clean in?

How long has the tank been set up for?

How long have you had the fish for?

Have you added any new fish or plants in the last month?

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Try doing a 75% water change and complete gravel clean each day for a week.
Make sure the pH is above 7.0 and the GH is over 250ppm.

If the problem is still there after a couple of big water changes then it is most likely a protozoan infection. Depending on what else is in the tank will determine what you use to treat if. Malachite Green will kill protozoans as will raising the temperature to 30C. And if you don't have Corydoras or wild caught angelfish or tetras in the tank you can add salt at 2 heaped tablespoons per 20 litres of water. If you do have cories and tetras in the tank then only add 1 heaped tablespoon per 20 litres.

To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

When you measure the height, measure from the top of the substrate to the top of the water level.

If you use a medication, remove carbon from filters before treating. If you use salt or heat you can leave carbon in the filter.

There is a calculator/ converter in the "How To Tips" at the top of the page that will let you convert litres to gallons.