Hi, please just relax you don't need anything else! You don't need any treatment & this is not of any concern. It will not stop you from having a baby & is not likely to be cancerous. All you need to do is to repeat an ultrasound
pelvis 6 weeks after the Ist scan to make sure it has disappeared. This is the usual fate for most of these tiny cysts. If is stays or increase in size ( which is very unlikely) then you need a gynecological review for further evaluation. Best of luck.