I’v got a 08 transporter that has a couple of paint chips that have got bigger than i should have let them (5p coin size) I need to stop these getting bigger so after removing the paint bubble and carefully rubbing down the spot whats the best treatment before dabbing paint back on.
Paint is black by the way

Ideally they should be shot blasted to remove any rust.
If it was me id rust remedy any spots. Etch prime. Then touch up.
Depends how mad you want to go with it.