HELP: Question about ingrown hairs?

I use a good razor and shaving cream, but I always get ingrown hairs under my arms. How can I help this? I never had this years ago, but now it has started. It is embarring to wear a tank or capped sleeves. I have tried exfoliating and putting baby oil, or shea lotion under my arms at night before bed. During the day I wear Secret deoderant.