Cybernetics, when damaged, get special 'wounded' descriptors differing from what skin does. However, they self heal over a period of time linked to your various health stats probably.
I am proposing that chrome does not heal without intervention by a cybertechnician or additional emergency technical aid. Not only would it add to fun cybernetic scarring after battles and the like, but I think it would push more business toward cybertechnicians and make the role more appealing on a reliable basis instead of occasionally.
Make a simple Emergency Cybernetics Repair kit that equates to a medpak for cybertechs, then the more expensive tools can be used for full repairs. Just spitballing, but self healing chrome has been a pet peeve of mine for ages because it heals so quickly I can barely even RP around having a giant gash across my cybernetic face, or a dented cybernetic arm.