ROS-induced　therapy　can　eradicate　breast　tumors　when　combined　with　thermal　ablation,　but　excessive　ROS　also　threatens　peritumoral　tissue　with　inflammation.　To　eradicate　tumors　and　avoid　inflammatory　sequela,　it　is　necessary　to　generate　ROS　in　treatment　stage　and　scavenge　ROS　in　prognostic　stage.　However,　it　is　a　great　challenge　to　reverse　ROS　in　different　stages.　Herein,　the　＇ROS　switcher＇　of　MnO2-coated　Prussian　blue　(PM)　is　loaded　in　hyaluronic　acid　methacrylate　(HAMA)　hydrogel　microspheres,　combining　ROS　generation　by　Mn-mediated　Fenton-like　reaction,　and　ROS　scavenging　by　Fe3+/2+　electron　transfer.　Firstly,　it　is　ROS　generator　that　oxidatively　damages　biomacromolecules　in　residual　tumors,　then　it　is　ROS　scavenger　that　reduces　pro-inflammatory　cytokines　and　oxidation　stress　in　peritumoral　skin.　Glucose　oxidase　is　immobilized　in　HAMA　microspheres　to　enhance　ROS　supply　by　catalyzing　glucose　into　H2O2,　degrading　MnO2　into　Mn2+,　and　providing　H2O2　for　a　Fenton-like　reaction.　After　MnO2　degradation,　Prussian　blue　is　gradually　exposed　and　scavenges　ROS,　thus　defending　oxidative　skin　damage　and　alleviating　ROS-stimulated　inflammation.　In　vitro　results　indicate　that　the　microsphere　supplied　sustained　ROS　for　up　to　5　days,　and　H2O2-degraded　PM　(0.2　mg　mL−1)　scavenged　500　μM　H2O2.　In　vivo　results　confirm　that　4/6　breast　tumors　were　eradicated　while　pro-inflammatory　cytokines　were　significantly　reduced　with　ROS　level　in　peri-tumoral　skin.　In　summary,　ROS　switcher　is　developed　by　Mn-mediated　nano-shell　peeling　and　achieves　tumor　eradication　and　post-operative　skin　repair　after　thermal　ablation　of　the　breast　tumor.　©　2024　The　Authors