I have to agree with the last poster... Hylands Teething Tablets are the BEST thing out there!!!!!! They are a natural herb and taste like a little sugar pill, and are the best thing ever made!!!
I would try the tablets and see how he reacts...It may help enough that the "weird" behavior subsides...It also could be that at this age they are alot more interactive...hence why so many moms join playgroups starting at this age...my son started popping out teeth at 4 months...2 at a time! So teething is a good theory...you can also give your Ped. a call and just ask what they think might be going on...They may just do what you are doing...educated guesses...only YOU know your child, and what may be going on...
The head butting and hitting himself may be reactions to teeth popping thru...each kid reacts differently...this may be hurting him alot and pressure may be helping him, so he does this....Hylands Teething Tablets work through their system to reach under the gums and numb nerves and help calm kids to help ease the teeth coming through....
Frozen waffles, Ice pops (with the plastic on), cold carrots, frozen washcloths, and of course, teething rings can all help...but keep in mind that some kids like HEAT and not cold, so if your child refuses the cold things, warm up a washcloth and see how he likes that...with the waffles, carrots and such, just watch for chunks and pieces so he does not swallow them....*HUGZ* I wish you the best of luck thru this hard time