The test for precancerous changes is the pap test not HPV testing. HPV testing is only helpful in evaluating certain equivocal pap tests and is not routinely performed. If your pap tests have always been normal that's a good sign but don't let that make you lax about getting them in the future. Your best defense against cervical cancer is to continue having regular pap tests. Fortunately, most people who are infected with HPV never develop any disease.
Dysplasia can progress into cancer if untreated.
If no high risk HPV is found then you can be reassured that it is highly unlikely there is any significant disease present. I have had abnormal pap smears, a couple of colposcopies. A friend of mine had her abnormal cells frozen. My doctor chose a LEEP procedure for me. It is a form of cone biopsy where a cone shaped piece of tissue is excised from the cervix.