How To Treat Rashes On Anal Area Of Infants?

i am breastfeeding and my 1 month old has continuously been gassy and seems to strain to have BM all the time, he also has rash around groin and anus area (for 2 weeks). in addition he has red bumps surrounding anal area(occurred last few days). i stopped using wipes and only wipe with wash clothes, i've tried triple paste (made it worse), tried vaseline only (not really working), baby powder only, i've been strict with my diet. what else can i do?