looks like aphids get some neem oil and some soap and spray them.

You can do a great deal to get rid of aphids with plain water and some squishing with your fingers. NO need for anything else when it comes to aphids.

Aphids can kill your plant if you continue to let them multiply like crazy. Keep after them on a regular basis; that's part of gardening.

Is your mint indoors? It looks a little etiolated as if it is lacking in light. Aphids love a stressed plant in an indoor environment where there are no predators and no adverse weather. If you can get the plants outside I think your mint will be a lot happier. Meantime hold the pot sideways under a running tap and swoosh the foliage with your fingers.