It's understandable to be concerned when you notice something unusual on your genitals. However, it is difficult to determine if the blister and scab were caused by herpes based solely on this information. Herpes lesions typically go through a distinct progression from blister formation to ulceration and crusting over several days.

If you suspect that it might be due to herpes or any other sexually transmitted infection (STI), I would recommend seeking guidance from a healthcare provider for proper diagnosis and appropriate treatment options. Remember, getting tested is essential for peace of mind and managing your sexual health effectively.

If you have further questions about herpes or STIs in general, feel free to ask!