Okay I am ready and I am posting my answer here.
I agree with you, this does appear to be confined just to the skin rather than involving the structures under the skin too.
While this being a new symptom, and also it is now possibly spreading too so I can fully understand your concerns, you are very much worried whether this could be something serious in nature. But with experience I can reassure you this is most likely not related to anything serious.
Since there are no additional symptoms like any rash, no actual pain, or any other local clear cut findings it will be difficult to arrive at a very specific diagnosis immediately, that too without examining the affected area. While there appears some yellowish hue too but it is still difficult to conclude anything. This needs to be examined by a Dr, and if required some investigations too need to arranged.
While this needs to be checked by your Dr in the clinic asap, however any serious possibilities appear very less likely.
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