thank you for your query.
The copper IUD has nothing to do with the pimples .
It could be responsible for your irregular periods
of late, however, that is also not likely, as your periods have been regular fora year.
Stress, anxiety, weight gain or loss, travelling are frequent culprits but you say that is not the case.
Other reasons could be thyroid
disorders or hormonal
medications being consumed.
PCOS is definitely one reason which explains the irregular cycles as well as the pimples, but not the ulcers.
you would do well to consult your doctor and have a thorough evaluation as rarely early pregnancy
, impending miscarriage
and ectopic pregnancy also could present this way.