I didn't look at the image as it's not a good way to really tell what's going on- the best way is for you to see a doctor.
If you saw a rash appear when you started shaving- that could be very normal, razor burn. You can help that by making sure you use a clean razor and wash with soap and water before and after shaving. Use a good moisturizing cream as well.
If you are sexually active- it's a good idea to get tested for STD's anyway- so if you have had sexual contact with someone and you are not sure of their STD status- go in to get tested.