I Am 21 Years Old, Nowadays I Feel Less Sensitivity

I am 21 years old, nowadays i feel less sensitivity on right testicle and the right side of penis is less sensitive than other sides. and a few month ago small blotches appeared on the skin of penis. can these blotches cause less sensitivity and less pleasure while having a sex, even blood flowing into penis is less than it used to be . when i visited a doctor and they determine testesterone level is normal as i remember it was 15. what can led to these problems. thanks in advance