Yes, you can take them as conclusive, and you really had no risk to start with.
One second of anything isn't enough to transmit anything. You can't really even call it frottage if it only lasted a second. Frottage usually means clothed, and if you were clothed, there is no risk at all no matter how long it lasted as STDs don't go through clothing.
One second of unprotected oral is really just a kiss or a lick, and there's no risk from that.
Remember that guilt doesn't equal risk.
Women get all kinds of things that can resemble STDs - UTIs, bacterial vaginosis, yeast infections, etc., etc. The list is long and varied.