Riding bareback and getting rid of farmers tan.

So I already have a wicked farmers tan. Practically looks like I'm wearing a T-Shirt when I have my shirt off. The rest of me is getting pretty tan, though.
I honestly don't want to bother with a rash guard or wetsuit. I'd really rather just go in with a pair of boardshorts and some sunscreen. Seeing as I live in SoCal, and I have a nice resistance to cold, I don't think I'm going to be screwed. But I'm really wishing I could get rid of this farmers tan.
What's my best bet? Low SPF sunscreen everywhere? Stick with my 50 SPF, but wait a little while to put it on my t-shirt area? I don't particularly like being super tanned, but I want to at least be even, so I don't look like such a geek (Though I totally am a geek...).
Also, while I was wearing a regular t-shirt while attempting to surf, I managed to chafe the hell out of my nipples. My left nipple even started bleeding down my chest (Which I didn't realize until my friend pointed it out.). Will that happen even if I ride shirtless, because of the wax? Or was it just because of the shirt? I guess rash guards are skin tight, the t-shirt I wore definitely wasn't.
I honestly don't want to bother with a rash guard or wetsuit. I'd really rather just go in with a pair of boardshorts and some sunscreen. Seeing as I live in SoCal, and I have a nice resistance to cold, I don't think I'm going to be screwed. But I'm really wishing I could get rid of this farmers tan.
What's my best bet? Low SPF sunscreen everywhere? Stick with my 50 SPF, but wait a little while to put it on my t-shirt area? I don't particularly like being super tanned, but I want to at least be even, so I don't look like such a geek (Though I totally am a geek...).
Also, while I was wearing a regular t-shirt while attempting to surf, I managed to chafe the hell out of my nipples. My left nipple even started bleeding down my chest (Which I didn't realize until my friend pointed it out.). Will that happen even if I ride shirtless, because of the wax? Or was it just because of the shirt? I guess rash guards are skin tight, the t-shirt I wore definitely wasn't.