Hello, I recently became more active with caring for my frogs that I've had for almost 2 years. In that period there were times when they were neglected due to me being busy or away from home. Of course, being the resilient frogs they are, I still have all 4 frogs alive and kicking. However, I noticed about maybe 4 months ago or so that my sole female frog has a dark dot covering about 3/4 of her head. She's the darkest of all of them and the dot is easily visible. There's been no obvious impact and she's been behaving normally, and in fact all of them have been healthy which surprises me because my tank is smaller and far less maintained than many others' on here. They've not had one single health problem aside from the dark dot on the female. Should I be somewhat worried, even though she has had it for a while now?