Yes that looks like orf.
Not sure what you mean by "orf cream". Orf is a virus and nothing stops it, but then you get secondary bacterial infection.
So wash it (Daz is good when it's orf! A vet told me about it and it does do a good job. And safer than hibiscrub around the mouth), then use an antibacterial spray.
It does take time to clear up.
Then think about how it is feeding. It will put orf on the ewe's teats, so unless she is vaccinated or immune, she may get orf on her teats which can lead to mastitis. Keep a very close eye on her, and her other lamb if she has two, or consider putting this lad on a bottle to protect his mum and any sibling.
Some powdered milks sting on open wounds, so when I used to get an orfy lamb I used to feed it on fresh raw Jersey milk. Or goats milk would be just as good. No stinging and they seemed to heal well once started on that. Of course keep everything thoroughly disinfected, and remember you have orf virus on you once you've handled this lamb or anything he has touched, so change clothes before going near any other sheep.
You may want to consider vaccinating your other lambs (and their mums if not immune) - but again, remember it's a live vaccine and anything that's been vaccinated plus you who did the vaccinating (and your clothes), and the pens in which you held the vaccinated sheep, can then spread orf to other sheep.