1) keep ur back breathing lor..coz sweat clog ur pores
2) use scrub...those back acnes use one..
3) shower ur back often lor..maybe got a lot dead skin ar..and etc..
this is how i do mine one...i think..2 and 3 is got much more better solutions..coz 1 is like..u wear shirt..working whole day..sure sweat
hard to keep ur back unclog with sweat i guess:)so..shower lor:)