Horrible razor burn!!

Ok so I feel like I’ve tried everything. I tried waxing myself *too painful* I’ve tried shaving different ways and using different techniques to prevent this but at this point nothing is working. It’s only really bad on my pubic bone area but it’s so painful. There’s many puss filled ingrown hairs and it’s disgusting. I bought Nair but haven’t used it yet because I didn’t have time last time I shaved and also wasn’t sure how safe it was to use down there. Any advice on how to prevent this? It’s killing me and I only shaved yesterday.