You don’t *HAVE* to do anything! Bumps, loops, and zig-zags are completely normal, expected, and even can be a good sign! They are what happens when a part of you dreadlocks tighten up before another right next to it. Think of a set of blinds with only one side pulled up; One side is tight and scrunched together and one side fans out and sticks out funny. This is the perfect metaphor for loopy dreads!
Some folks like the character that loops bring to the dreadlocks and, in fact, celebrate them. For these folks, obviously, the course of action they prefer is to do nothing. Most loops eventually even out (to a degree, anyway) over time simply with patience.
However, if you don’t care for your loops, there are a couple other options:
1) Palm-rolling: With regular, religious palm rolling, (especially done while your locks are damp after washing) it can encourage the loops to lock into your locks and help the portions of your locks that are dreading more slowly catch up. (see photo at above left.)
Note that not ALL bumps are fixble, however. Only if you catch your loops while they are young and mostly unlocked hair can they be influenced to lock into a different shape, if desired.
Some sources suggest that you can use felting to straighten out established loops and bumps, but we do NOT recommend it as felting causes a lot of breakage which can lead to dreadlock loss (entire dreadlocks breaking off).