Thanks for the information
There are a few things to consider here
It can be a post inflammatory pigmentation
Callosities can appear like this as it seems you have a dry skin and it seems to develop cracks in it.
On occasion repeated trauma from the foot wear can lead to such slight discoloration of the toes as well.
Secondly for your symptom of tiredness i would suggest to have your thyroid function tests done as well
Hypothyroidism can cause extreme fatigue and also dry skin.
I would also suggest a complete blood count and routine chemistry as well including a kidney and liver function.
You can apply some emollient to moisturize your skin as well. Simple Vaseline/petroleum jelly will help as well
Feel free to ask if you have any more question
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