What Causes Yellow Discharge With Rashes On The Lower Legs And On Arms?

recently my partner has been sleeping with another person. i have noticed ive been getting a vaginal discharge that is of a yellowish color. also and i dont know if this is linked but i went swimming recently in a lake and seem to have bites or something coming up, mainly on the lower parts of my legs near, my knees, on my arms and one on my cheek. i dont know if ive looked into this too deeply but could this be herpes. PLEASE HELP ME!!!!