I woke up with a painful lump in my leg?

I woke up with a painful lump in my leg. I know I haven’t been drinking enough water and forgot my iron supplement for the last couple days. I just took it now along with some vitamin C and an ibuprofen and lots of water. I’m 29 and a healthy weight. I walk a lot, but that is pretty much my only exercise. Will this go away on its own or should I be concerned?

Age: 29
Female
Medications: Wellbutrin, Methimazole, Iron supplement, the pill