Penis not erected. Tell what to do?

Almost 4 months ago I hit my hard penis on the hard side pillow many times. After that my penis stopped erection. After 15 days it erected but not regularly it was erected before. In 4 months penis erected only few days. Last 2 months I noticed that penis not erected by own but use my hand to get my erection. I don't masturbate regularly. Before this problem occurs I only masturbate once in a month. But last 4 months I don't masturbate. But now a days I noticed that penis not erected by own and when I use my hand to get penis hard it was getting hard but my root or base of the penis not getting hard and penis is not standing , it lying down left . What is the problem happen? How I will get my full hardness.? Is there massage oil to get it hard, and my tip of penis also little painful Please tell what to do? ‌