Once you 'finish' your rads, @Aska - the 'cooking' actually continues for a while, so further redness/breakdown may occur - so it really depends on whether your skin breaks down (ie possibly open lesions) and how comfortable you are in returning to work.
I was lucky & really only had redness/rash .... Some members have continued working throughout their Rads without issue ... but not everyone is affected in the same way. Just keep your lotions & potions up to your skin and let the Rads Nurses (and your Rad Onc when you see them) if you notice any serious burning/breakdown.
take care & all the best xx