I recommend 100% tea tree oil, applied to the underside of the cut edge of your fingernail with a 'cotton bud'. Since it is your fingernail, you will need to be careful not to put your fingers to your eyes or mouth after applying the oil.
There should be no harm in doing this daily, but three times a week will work, until the fungus-affected part of the nail has grown out.
This was an inexpensive and successful remedy for me after two purchases of very expensive pharmaceutical preparations failed.
Apparently wearing acrylic nails is the root cause of your nail fungal infection. I suggest that you steer clear from using acrylic nails and instead allow your nails to breath. It will also be helpful if you apply tea tree oil regularly on your infected nails to prevent the fungi from spreading. You can also purchase an otc anti-fungal product for nail fungus such as Fungusil. You can use it along with tea tree oil as it will help make it more potent in eliminating the fungi living in your nail bed. Of course, do not forget to practice good hand hygiene. As always, cleanliness is the key to properly address nail fungus.