It's completely normal. If it continues you can try adding more bac water. Some people are more sensitive and if you have too rich of a concentration it can aggravate your skin. It's nothing to worry about, it happens to me from time to time.
Damn, that's interesting. I've gotten itchy several times and thought nothing of it and nothing has ever came from it. Now when I say itchy I don't mean life in scratching my skin off or I'm going to die but just a slight itch for a few minutes. I researched the hell out of it and the only answer I could find was it was probably due to the concentration of the reconstitution.
Yeah I'm doing 2mg of tb500 a week which is a full vial. I figured what hell I'll just use less bac water but it might have been too concentrated. The redness and bump are almost gone. The itchiness was comparable to a insect bite