If you are able to identify who has touched you without your consent, you can take this information to the bar/club manager/ owner or security and let them know so that they can deal with the person and situation.
If you have not been able to identify the person, I would assess how you are feeling and if you want to remain at the venue. If you are feeling uncomfortable you do not need to stay - If you have friends who want to stay and are pressuring you to stay, try and call someone who may be able to come and get you so that you can leave.
Stay close to your friends or who you are at the venue with.
If you feel the venue is not handling the situation appropriately you are able to contact the police the next day or use some crisis services for advice and support.
