Orf is a virus so antibiotics have no effect whatsoever on the underlying infection. They will however help the sheep fight any secondary, bacterial infection should there be any.
If you have orf in a batch, get them all onto soft grazing - no thistles or anything else scratchy - if at all possible. The virus enters through broken skin, so lambs eating thistles is a classic point of entry.
Watch your ewes carefully for any signs of sore udders - the lesions on the lambs' mouths can infect the udder if there are any nicks or abrasions there. If this is your first year with orf, the ewes may not have any immunity, so could get an infection leading to mastitis if there is a secondary bacterial infection there. If you have had orf on your farm for a while, the ewes will probably be immune, so hopefully there shouldn't be problems with udders, but keep an eye on it nonetheless.
For uninfected first stage lesions, Septiclense is as good as anything for keeping them clean and protecting against infection. Iodine would be just as good. (And Daz washing powder does work - don't ask me why Daz, but it does!)
Kept clean and off scratchy grazing, they should heal and be fine. But it is very very sore, and if severe can block noses and make eating hard, not to mention passing infection from lambs' mouths onto ewes' udders, so if you find your farm has orf and you get more than one or two cases each year, then prevention is probably worth thinking about.
The vaccine does work but it has to be applied correctly. It is a live vaccine, and has to be applied onto
broken skin - you have to scratch
really hard with the little jabby applicator, then we do a cross so that some of the vaccine is spread into the other arm of the cross. We find the inside of the thigh to be a good place to do it - you need bare skin that you can pull taut so that you can break the skin with the applicator. We tip the lambs on their bottoms to do it so we can see that we've made a good job of the scratch.
The vaccine will provide protection only to lambs which have not already become infected, of course - so may be of limited value in a batch that is already showing a lot of lesions. But if you have a bad year with orf, you may want to vaccinate the following year as a preventative. (We did this year, having had quite a few sore lambs last year.)
The tubby buckets are a mixed blessing. On the downside, lambs congregating around the buckets can spread foot infections - and also orf!
If you haven't had orf yourself, then it is worth trying to avoid it - it is pretty painful. But it really isn't the end of the world, and once you've had it you won't get it again, so don't be too worried about it.
Started writing the above this morning and have just come back to complete it, of course to find some new posts since I started writing mine. I think I'm probably just paraphrasing jaykay and VSS but since I've written it I'll post it anyway. I haven't ever heard of thistle prick as distinct from orf, but it's possible.