The Bitch Tit

One of the more unpleasant side effects of some steroids is gyno. Normally your body tries to keep a healthy balance between male and female hormones. When you start injecting yourself with steroids the amount of male hormones in your blood gets abnormally high. Your body reacts by starting to break down these male hormones into other compounds which in many cases are equivalent to the female sex hormones (estrogen).
The net effect is that with some steroids in addition to the elevated male hormones in your blood you also get high amount of female hormones. This can have various effects, some of which like water retention are not always nasty - the water makes you look bigger (although somewhat puffy) and it actually helps relieve the stress in your joints when training. The nastiest effect is gynecomastia, gyno or just bitch tits. Basically you just get breasts.
Maybe week and a half after I started taking steroids I had the first symptoms - my right nipple felt itchy and on the next day it was already swollen. It felt like there was a hard lump beneath the nipple and the skin above it was red and painful.
I was really concerned that the process was not revercible and I will always have this lump. Fortunately this was not the case. I started taking Nolvadex - a medicine prescribed for breast cancer, which prevents the estrogen in your blood from binding to the appropriate cell receptors, thus rendering it ineffective. A 3-4 days afterwards the lump was gone. I am still taking 1 Nolvadex pill per day and I plan to continue doing so even several weeks after finishing the steroid cycle so I can prevent such incidents.