Thank you everyone for your advices.

I was so overblown for the past two days. Looks like I have finally got it under control. She's still a bit sore down there but at least she's not raw. I am relieved to see that her skin is not so red looking now. Back then, it was like a cherry tomato with small blisters.
It's so hard to watch the little one suffer. I think ever since I've had my own kids, I am more aware and saddened by what happens to the news when kids are a concern.

I have stopped using commercial wipes... didn't know that they can also cause a reaction even when indicated for sensitive skin.
I have applied a milk cortisone before I applied a layer of Zincofax extra strength (zine oxide 35%)
Gave her plenty of diaper free time
Spent a night without sleep laying her on my chest exposing her bottom as the back side sleeping made her bottom more irritated
Used a bucket of warm water and soft cloth to clean her
Changed her nappy as soon as it's soiled
Tried different brand of nappy (but don't think this is what it help to lessen the rash)

So far, she's gotten better from it. I think I will stay away from commercial wipes forever and just go with the idea of ziploc bag with cloth and water.

Now that I have got the nappy rash under control, I have another problem... I noticed some blood coming out from her vagina... something like menstruation. I looked up and it says it's normal for baby girls to experience this the first week of birth. It's a few drops of blood every time I change her, is this something I should be concerned for? DD1 didn't have this so I have no clue?

Thank you again for everyone's kind advices...