Hi!
Please see a vet. Any eye problem should always be seen promptly because eye injuries can deteriorate very quickly and may at the worst end up with needing an eye removal operation. The more quickly you see a vet, he greater your changes of a quick and straight forward recovery.
If your piggy has come with the problem, then you can reclaim the vet cost from the seller as part of your customer rights for having been in effect sold faulty ware. The longer you wait, the less you can prove that the seller is at fault.
New guinea pigs: Sexing, vet checks&customer rights, URI, ringworm and parasites
Thick yellowish/greenish/orangey around the eyes and nose are a symptom of an advance un- or undertreated respiratory tract infection, which can be fatal or cause permanent damage in the airways.
Any transparent crusts are a sign of a persistent irritation in the eye (tear fluid); this can range from an actual eye infection, something stuck under an eyelid or a potential conjunctivitis. Treatment with antibiotic eye drops/gel, lubricants and painkiller will be prescribed by your vet according to their findings.
Any milky crusts are from not properly absorbed eye cleaning fluid, which piggies use to keep their eyes clean and hydrated instead of constantly blinking like we humans do. If that happens constantly, the tear duct may be blocked.
Guinea pig body quirks - What is normal and what not?
Both of these helpful links are part of our much more comprehensive practical information collection, which you may want to bookmark, browse, read and re-read at need:
Getting Started - New Owners' Most Helpful Guides
We also have got a very helpful emergency and bridging care advice and practical tips collection; again useful for bookmarking, so you have it handy. Emergencies have a nasty tendency to happen at the most inconvenient of times so you can easily access all the necessary practical advice in one go when in a panic:
Emergency Resources and Critical Illness Care - Contents list and subforum link