Thanks for the answers to my questions.
I wouldn't worry about leaving tick parts behind (the head) if this is, indeed, a tick. It's something of a myth that all the parts need to be removed at one time. If the head is left behind, it may cause a little local irritation but it will fall off within a few days; the last thing you want to do is try to remove it with a anything sharp.
I would gently pull on it to see if it comes off; if not, then it may be a skin tag after all. If that's the case, then these are benign and bother us more than the dog in most cases.
I doubt that this tick or tag has anything to do with her other symptoms. Gastrointestinal distress such as you're seeing can be secondary to a wide variety of things ranging from dietary indiscretion, viral or bacterial diseases, Inflammatory Bowel Disease, foreign body.
My suggestions for her nausea and being "off" are as follows:
1. Withhold water for 8-12 hours; just give everything a chance to settle down; then offer small amounts of water or pedialyte through the day.
2. Withhold food for 12-24 hours and then offer a bland diet of 1 part boiled chicken (or hamburg) to 4 parts 20-minute white rice. Feed only a small amount at one time, 3-4 times through the day. I would not feed any regular dog food.
3. You can give over the counter Famotidine if available in Ireland which might help with the nausea.This is available at most human pharmacies here in the States but I'm not sure what you'll have there.The dose would be 0.25 mg/lb twice a day.For example, the dose for a 30 lb dog would be 10 mg twice a day.
Other options include Omeprazole at a dosage of 1/2 mg/lb once a day. For example, a 30 lb dog could be given 10 mg once a day.
Ranitidine can be given at a dose of approximately 1 mg/lb which would be 1/2 of a 75 mg for a 30 lb dog twice a day.
Meclizine HCl (Antivert is one brand name) could also be used. It's an anti-histamine that can be used for motion sickness but it has anti-vomiting properties, too. The dose would be 2 mg/lb once a day. For example, if your girl weighs 30 lbs, her dose would be 2 tablets of a 25 mg tablet once a day.
Sedation might be seen as is common with some antihistamine drugs, though.
I would also try to prevent grass ingestion since this can be very irritating to the stomach and esophagus and could perpetuate the problem.
I hope this helps and that she starts to feel better soon. Deb