4 months period not regular, spotting in btwn period, report showed cyst with 3.4cm in left ovary, doc said I ovulated recently and normal, any treatme?

IRREGULAR OVULATION. Hi. If you are not trying to conceive, having irregular ovulations is ok. If you are trying to become pregnant, the irregularity of ovulation makes the timing of sexual intercourse more difficult. Also, less eggs are produced each year, which can reduce the chances of getting pregnant. That said, being 25 years old means that your egg quality is good, so the possibility of conceiving is excellent.
No. Usually cysts that are simple in natures will resolve over the next cycle or so. If you are not having pain you may be fine. Your doctor can rescan you in a month.