Skin scrapings, tissue culture and blood tests can give information about HSV infection. Often these are not performed since the appearance is so classic for the illness. If you would like to determine if the rash is from type 1 or 2, tests can possibly tell the difference, but the problem is that sometimes the test says there's no viral infection when there obviously is one by examination. This is called a false negative test, which is common with these viral tests since they don't have enough power to rule out an infection.
HIV testing is recommended for those suspected of having HSV since the risk factors for HSV and HIV are the same. This is something to seek from your primary care doctor or the county public health clinic since an urgent care is usually not set up to provide the extensive counseling needed to educate you about the particulars of the test. A benefit from getting it at the county public health clinic is that some offer confidential testing where your test results are associated with a number, reducing the risk of inadvertent release of this very sensitive information to parties you would like to keep it from.