Tip of my dog's vulva is red and irritated?

[bibyenish]

The TIP of my dog's vulva is red. I could tell that it bothers her very much because she has trouble walking. When she walks, she keeps sitting down. When she sits down, she rests on the left side of her butt with her right leg up/. She also licks her vulva a lot. Also, she seems to be getting more and more unhappy as the time goes by and doesn't want to do anything active.

I don't think the vulva is swollen, but the tip is definitely getting redder. The day before, she had the hair around her vulva trimmed by my brother, and I thought maybe she got cut. However there is no bleeding and my brother is sure he did not cut her at all. Regardless, I think it's becoming infected/inflamed.

Unfortunately the vet is closed tomorrow, but what can I do in the meantime to help ease her pain/discomfort? Can I put Neosporin on her vulva or is it not safe? I have another ointment that was prescribed to her long ago, called Animax Ointment. The ointment was for her vulva when she had a different infection. I tried putting that on her but I don't think it's helping.

She is a 4 year old Shih Tzu and has already been spayed. Any help is appreciated! Serious answers please. Thank you!