I Have Been Experiencing Raised, Red, Itchy Lines On My

I have been experiencing raised, red, itchy lines on my lower leg (mostly right leg, one on left leg). The first one was the worst. It started as what looked like a simple ingrown hair, although I don't think that's what it was. Over the course of 2-3 days, it expanded and formed a line roughly 3 inches long. It lasted for 2.5 weeks, really itchy and weeping clear fluid. Now it's healed, forming a normal scar. I had a few that were much smaller at about the same time, but nothing since - until last night. I have a new one forming on my right ankle. It started as a half inch hard, raised red line, and is itching terribly. It's a little longer this morning, and oozing a little bit. What on earth is this? Should I be concerned?