Hi, welcome to HCM.
FIrst of all, TSH is the hormone which maintanes the T3 and T4 balance. SO, it is the guardian of thyroid
WHen thyroid is hypofunctioning then the TSH becomes elevated and causes normal functioning of thyroid..
So, if you do not take thyroxine
then TSH level
does not go back to normal level and it may lead to enlargement of thyroid gland and it may lead to any neoplastic changes also.
SO, you must take that thyroxine daily as per schedule.