Just found this thread- both points relevant to me!
I used to have small nipples. After feeding ds1 for a year the right one was very big (he would only feed on the right hand side). Now after feeding ds2 for 13 months and still going the left one is also big (used to be kind of non existent/inverted- now most definitely isn't.)
I've had mastitis 3 times now - twice with ds1 and once with ds2. It really helps if as soon as you get the first hint of it you jump in a hot bath and drape hot flannels over your boob- then kind of squeeze the affected area to get rid of the milk. Do this as often as you can. The first two times I got antibiotcis realy quickly athough I still felt grotty for a while. This time I used the homeopathic remedy phytolacca- and it really helped (I did get antibiotcis as well but I think I dould have done without them- my Mum was there when I got them and she had a breast absess with me so she was shoving them down my throat!)
The first few weeks of feeding can be rally sore- especially if you have cracked nipples (which can lead to mastitis). I remember with ds1 screaming and holding dh's hand as he latched on. It was horrendous. Midwives gave me conflicting advice as did breastfeeding counsellors. One did tell me it couldn't possibly hurt as much as I said (I was in tears). In the end I introduced 1 bottle a day,- much to one of the counsellors disgust (which I eventually dropped), gave up on the left breast, and took it day by day. Suddenly it didn't hurt anymore- and then - wow - what a pleasure. I didn't play it by the book at all- but having that few weeks with one bottle allowed me to conitnue feeding. Then I was able to go back to exclusive feeding. Before giving the bottle I fed from one breast (so the bottle was kind of half a feed).
Good luck this time. I did find it easier 2nd time round although we still had problems. DS2 didn't put any weight on- as he had an undiagnosed (until 6 weeks) umbilical infection. I was told to introduce bottles (which I did- without that I don't think they would have looked for the infection), but again I would breastfeed first then top up with a bottle for the remainder of the feed. Once the infection had been cleared he started to really thrive and I was slowly able to reduce the number of bottles. It took a while as ds1 was just going through an autism diagnosis and to say I was stressed would be to put it mildly (milk supply wasn't great- helpful advice- "you need to relax" hmmmmm) Eventually we got there though- back to exclusive breastfeeding.
So give it a go. If it does hurt then try taking it one day at a time- it does stop. Try finding a combination of bottle/breast/expressing that works for you if you really can't bear to go through every feed (and it will be harder with an older child) If it doesn't work out though- at least you gave it your best shot.