One thing you don’t always get offered, but should, is Omeprazole alongside steroids. It protects your stomach. The steroids can make you feel quite bleugh in the oesophagus, stomach, general digestive areas. You could phone your doctor tomorrow and ask for a prescription ASAP. It will help. Meanwhile, try getting some liquid Gaviscon, that should help in the short term.
Steroids do as well have a habit of making you a bit hyper, and can lead you to teeth grinding / gnashing. Don’t be surprised if small things really p*ss you off either. It’s partly the lack of sleep and partly the effect of the steroids. (Hence ‘roid rage!)
I’ve generally found that after the steroids I end up feeling bruised like hell. That could start earlier (as said before, we’re all different in our drug reactions and tolerance).
The foul taste in your mouth (sort of metallic) can be disguised a bit by mints - try nibbling extra strong mints, you can make one last a really long time that way so your mouth always tastes minty rather than like someone shoved an iron bar in it. It might help with the teeth gnashing too. Chocolate also disguises the taste, but if you sit and eat chocolate all day, it’s bad for you (apparently - who knew?)
I tended to find that coffee tasted horrible on steroids so switched to tea or hot chocolate. This is in spite of the fact that I have a proper black coffee habit, all day long normally.
The worst thing about steroids though is their unpredictability. You may find that they do exactly what you want them to (ie bring the relapse to a quicker end), but sometimes they just don’t. And it doesn’t mean that if they work for you they always will and vice versa, it’s just random. So this time they might do their job and next time not. It’s that flipping random.
And don’t forget that taking them too often can cause problems with bone density in later years (osteoporosis). The advice used to be not more than twice a year, but this now seems to have changed to three times.