Hello and welcome. My name is ***** ***** I'm a biologist with a special interest in avian health. I'm sorry to hear your bird is having a problem.
What you have described is common when a bird vomits (which is different from regurgitation). Since you can't handle him, it can be difficult to check him out. It would be a good idea to gently wash the wet area with plain water. Wait and see if it happens again. Vomiting is usually a sign of illness, and if it happens twice, a vet visit is needed.
Other symptoms of illness to watch for include appetite loss, fluffed up feathers, lethargy, discharge from the nose or eyes, and sneezing or coughing repeatedly.
If your parakeet ends up with a wet head a second time, something that requires treatment is happening. You don't necessarily need an avian vet. there are other vets who are competent to treat birds. You'll need to make a few calls to find one who does. This link may help:
If you have more questions, just let me know. I hope this will be a one-time occurrence, and your bird will be fine.
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