I'll jump on the opposite end of the bandwagon and say that my lesser gets random pink spots all over her before shedding. At first I thought burn, and freaked out with trying to figure out how, but it slowly took over her whole belly and she went into shed. I suppose since you don't know the snake, wait and see if it goes away, she sheds, or if it continues without a shed - if it's the latter, its probably burns from a previous owner
ETA: I would also give her a bigger water source to help make her more comfortable in the meantime, since she obviously shows interest in soaking