It’s difficult to be certain from a photo, however, I can’t see any of the usual scabbing or flaking of skin that you would expect with ringworm. From the photos it does look more like a puncture wound from a bite. The best thing to do for now is to clean it with some home-made saline(salt in warm water) and keep a close eye on it as white wounds do have a tendency to develop abscesses if you are unlucky. If it is a bite wound there will probably be a second puncture somewhere else under the fur (think top set of teeth and bottom set of teeth). It is possible that it is a scratch or scrape from some sort of encounter with her new friend. I would also have a suspicion about the nature of the new bond as a wound on the neck would indicate the potential for their having been some sort of altercation and this being a defensive wound. I have no information about how the bonding was carried out or how the piggies have been together but I’m going to link for you the Forum guides to bonding and behaviour. If you see any escalating behaviour you may need to step in and separate them permanently. In general the rule is that once blood has been drawn, piggies shoukd be separated, however, if this was an accident rather than a fight Then there is the potential that the bond may work. If it is a bite please be prepared that you may need to separate them permanently.
1 List of dominance behaviours in ascending order of aggression
2 What may cause this type of behaviour in boars?
3 When do you see these behaviours in sows?
4 What can trigger fall-outs?
5 Further helpful guide links
I thought it may be handy to have a sticky on typical dominance behaviours for a reference - hopefully it may help humans understand guinea pigs and their behaviour a bit more and hopefully prevent some avoidable problems!
1 List of dominance behaviours...
1 Causes for bonds to fall apart
2 Bonds in Crisis
- What are the signs of a dysfunctional bond?
- Bullying
- How can I test whether a bond is no longer working?
3 Failed bonds and what next?
- What to do if my piggies have had a major fight?
- When rebonding doesn't work out
1 Causes for bonds to fall apart
Every fall-out has of course its own...