AbstractMethylated circulating DNAs (ctDNAs) have recently been reported as a promising biomarker for early cancer diagnostics, but limited tools are currently available for continuous and dynamic profiling of ctDNAs and their methylation levels, especially when such assays need to be conducted in point‐of‐care (POC) scenarios. Here, a self‐healing bioelectronic patch (iMethy) is developed that combines transdermal interstitial fluid (ISF) extraction and field effect transistor‐based (FET‐based) biosensing for dynamic monitoring of methylated ctDNAs as a prognostic approach for cancer risk management. The projection micro‐stereolithography‐based 3D patterning of an Eutectic Gallium‐Indium (EGaIn) circuit with an unprecedented 10 µm resolution enables the construction of self‐healing EGaIn microfluidic circuits that remain conductive under 100% strain and self‐healing under severe destruction. In combination with continuous transdermal ISF sampling of methylated ctDNAs, iMethy can detect ctDNAs as low as 10⁻¹⁶ m in cellular models and is capable of phenotypic analysis of tumor growth in rodent animals. As the first demonstration of a wearable device for real‐time in vivo analysis of disease‐indicative biomarkers, this proof‐of‐concept study well demonstrated the potential of the iMethy platform for cancer risk management based on dynamic transdermal surveillance of methylated ctDNAs via a painless and self‐administrable procedure.