HI, thanks for using healthcare magic
The blue discoloration is due to reduced
oxygen supply to an area.
This can be related either to a reduction in blood going to that area or a reduction in the oxygen present in the blood (the amount of blood going is the same but there is less oxygen in it).
There are a number of different conditions or issues that can cause these problems such as : (1)temperature drop though you mentioned that it wasn't too
cold. A reduced temperature is associated with
vasoconstriction which is a narrowing of blood vessels
(2)anemia-low blood count can also cause anemia because it affects the oxygen going to the different areas of the body. A full blood count would determine if this is present
(3)narrowing of blood vessels in the area
(4)change in the
heart rate. In this case, you would likely notice palpitations or have
dizziness, lightheadness,
shortness of breath, clammy feeling, sweating
(5)change in blood pressure
If you continue to have symptoms then you would need to see your doctor for an assessment which would include physical examination and blood tests.
If there are any changes in the heart rate then an ECG , which looks at heart rate and rhythm, would also be needed as well.
I hope this helps