I have noticed two small hump type on the back of my Penis. One is small and slightly black in center with white surrounding and other is more small with dark skin. I am not having any pain or itchiness in either of them. What can this be? Also I have had Erection issue 4 days back so I went to Sexologist and he conducted physical test and Ultrasound and said its normalised and just because of my Stress (which I had been through quite a lot this time) and will be resolved in few days after that now this Erection issue is resolved as I am getting Erections today. Can these things be related? Pls let me know. I didn't have this Hump type thing on day of Ultrasound 4 days back.