I am no doctor, but I know a lot about this topic, because the same thing happened to me.

The exercise you where doing is called Jelqing. IT IS EXTREMELY DANGEROUS! I caused nerve damage to myself with that exercise.

I injured myself pretty bad with Jelqing, and was about to give up until I started researching nerve damage for like 6 hours a day for a week.

These are things that I do to heal nerve damage...

1. Stay off the bicycle

2. Do not let your penis flop around a lot (avoid running)

3. Take Male Reproductive Factors by Micheals
This has a ton of Zinc and B-Vitamins in it. Very good for erections.

4. Take Ginseng
This helps with erections.

5. Take Ginkgo Biloba
This helps with blood flow and erections.

6. Take Nerve Blend SP-14 by Solary
This helps repair the nerves and calms them down.

7. Take Organic Flax seed Oil
This helps repair and strengthen the nerves.

8. Take the cell salts Ferrum Phos., Kali. Phos. and Mag. Phos. by Hylands
Good for nerve growth

9. I am researching Advanced Yohimbe-Plus by Iwin Naturals
I think it may help, but have yet to try.

I started taking this stuff 1 month ago and I already feel MUCH MUCH BETTER!!!

GOOD LUCK and remember if your are on any medication or have a serious illness talk to your doctor before taking any of this stuff.