hello and welcome to HCM forum,
according to the history presented by you i would like to inform you that i won't be able to provide you with the diagnosis , as clinical check up needs to be done first.
you have mentioned that you have sensitivity ,this is due to recession of gums and dentine exposure.
These holes seem to be periodontal pockets, and need a dentist's attention.
as you said your teeth are crowded, therefore in such cases, periodontitis
is very common.
i would recommend you to visit your dentist, get your teeth cleaned, as well as maintain your oral hygiene
i wosh you good health,