Sounds like there is a reason they are substitute vets. Is there any other "real" vet you can take her to before your vet is back. Two weeks will be agony and seem like an eternity. Keep a close watch on the lump. But do not give it so much attention that Luna becomes aware of it. Although it sounds like she wouldn't be able to reach it. I will pray that it is just a lump and nothing that needs any attention or causes her (and you) any difficulty. Please give Luna a big KISS.