Its not very clear from the pictures what we are talking about. So share any better pictures if you have.
And HITH is not commonly reported in Aros, as per my understanding. However Head-rot is common and mainly associated with the presence of activated carbon in the filters. And if your carbon is very old, then it is more troublesome, please remove it immediately.
The little dots on the head, side-body are part of its body design. Just check if the dots are synchronous, that is there is an identical one on the other side of the body, then nothing to worry.
And hoping that you have reduced the temp already. Is he eating properly?