The circumcision is correct if approved by the expert who performed it that he took the foreskin off during the procedure.
Due to the penis being a living tissue, it may sometimes change in size where all the penis head is exposed, and at other times, leaving some of the head covered as mentioned in your example.
After consulting with a brother I know who works in this field, and who is an expert in circumcision, he confirmed that your issue is common and wouldn’t be classed as ‘uncircumcised’. Many other adults he has checked also experience this after they were circumcised when younger.
Ulema say that the important part is for the top part of the head to be exposed (meaning the urinating hole).
Some extra skin sometimes going a bit over the head when it’s cold wouldn’t invalidate the circumcision as at other times the head will be fully exposed in a normal state.
The ulema also state that one can rely on those who perform circumcision to take the correct amount. So you may trust their judgement.
May Allah grant you success