Sounds like you've got some tendonitis started up there. It sucks cuz once you get it never really goes away. Something will always aggravate it when you least expect it.
I have a similar problem (though I have tendonitis in many more places as well) - I had to take a break from skull crushers and close grip presses because I just couldnt' support that angle. Same w/ tri dips. If it just plain hurts, I'll stop for awhile. When I can work back, I currently do the following :
Super set of:
- cable rope grip tri pressdowns
- cable rope grip OH tri extensions
DB tri kickbacks
And all of these I focus on the tricep - i.e. visualize it and go for full extension and control so I can get a sicko burn on it. As noted above - these allow you to isolate the movement of your elbows by locking them at your sides -this helps to support and protect them from the additional stress of being the only support point like they are on presses & skull crushers.
Also in terms of volume, I usually train tris & chest so I'm hitting them a lot overall. I don't need to do a crapload of accessory work.
Additionally, right now if it really hurts, I'd ice it at least a couple times /day, ibuprofin (don't load it - it can be rough on your stomach lining in large amounts) helps, and also make sure that you've got enough water intake and good EFAs in your diet to support joints / tendons.
If you're using any winstrol or any AIs like arimidex, etc, those will also dry the fuck out of your joints and further irritate the tendonitis you've already got going.