Voice problem. Suggest some treatment.

Sir, I have been experiencing voice hoarseness in my throat for the past one month. I have already consulted a physician and an ENT surgeon. I also underwent a laryngoscopy. The ENT doctor diagnosed swelling on the voice box (laryngitis). I have been taking the prescribed medicines for the last 15 days. There has been some improvement, but the problem is still about 50% present. I take steam 2–3 times a day. After taking steam, my voice improves temporarily. I also have a cough. At night, I experience dry cough, and during the day, the cough is mostly with mucus. I feel phlegm in my throat. After speaking for some time, my throat feels tired, and my voice becomes heavy or starts cracking. Sometimes, my voice becomes thin or produces a whistling sound. This problem started suddenly on 27th February along with cold, fever, and sore throat. After a few days, the other symptoms improved, but the voice problem still persists, as I described. Please suggest some treatment.