Most cases of Laryngitis are viral infections and not bacterial infections and if the Laryngitis is viral the antibiotics will not do anything for the Laryngitis.
Antibiotic medicine only treats bacterial infections and not viral infections.
The Laryngitis should clear up and go away within 1 to 2 weeks but if the Laryngitis lasts longer than 2 weeks then a doctors visit is recommended because it could be bacterial and need antibiotics to treat.
So if it's just a viral infection causing the Laryngitis all you can really do is rest your voice and try taking some throat lozenges to help with your throat.
You can also drink some honey in some warm tea to help soothe your throat and within 1 to 2 weeks the Laryngitis should be gone and you should be feeling better.